Having celebrities involved with wrestling is a long tradition particularly in the WWF/E, but in reality there has always been celebrities involved with wrestling. Now in the pre-Wrestlemania days the only celebrities involved were usually athletes. There were plenty of times where a famous boxer or football player was brought in as a special guest referee or ring announcer. And especially in football and a few cases of boxers, some would step in the ring and actually wrestle. There's been a long tradition of football players having side-careers as pro wrestling going all the way back to Bronko Nagurski in the late 1930's/early 1940's.
But there have been plenty of famous boxers from Rocky Marciano, Primo Canera, Joe Louis, Muhammad Ali, and more recently Buster Douglas, Mike Tyson, and Floyd Mayweather who have gotten involved either as guest announcers, referrees, or wrestlers.
But again before Wrestlemania it was mostly football players, boxers, and/or other athletes that participated. You never saw for example famous musicians like the Beatles, Frank Sinatra, or Elvis Presley (who was supposedly a big wrestilng fan actually) perform at wrestling shows. You never had famous tough guy actors like John Wayne or Steve McQueen come in as a special "enforcer" to rough up the heels for a good pop. That didn't come until after Wrestlemania.
And I know having celebrities involved has always been considered a horrible thing by most wrestling purists, but the truth of the matter is wrestling wouldn't be as big as it is today without having celebrities involved. Everyone credits Vince McMahon, Hulk Hogan, and/or Roddy Piper for the success of Wrestlemania and the explosion of the WWF. But the truth is, it was MTV, Cyndi Lauper, and Mr. T who made non-wrestling fans pay attention to the WWF. It was considered radical at the time having Mr. T, an actor wrestle in the main event of a huge wrestling show, and having Billy Martin, a baseball manager as the guest timekeeper, or having a performer like Liberace open the show. But having all of these pop culture figures appear on an intriguing show is what really put the WWF over. Would Piper have been such a pop culture phenomeon and great heel without his actions against Cyndi Lauper who was at the time the most popular female musician in America (Madonna would soon eclipse her of course, but yeah). Hogan wouldn't have been as big had he not appeared in Rocky III with Sylvester Stallone, who was one of the biggest movie stars in America. And then there is of course Muhammad Ali who was apart of wrestling his entire career. Him being the guest referee for the main event brought more legitimacy to the event and wrestling as a whole.
Like it or not, celebrites make non wrestling fans pay attention. And while I'm not a fan of the guest host thing for the most part as it's served for some really lame crappy TV, they still do their job in getting non wrestling fans to pay attention to wrestling.
As far do they always work out, of course not. Most celebrities work well in bringing in viewers but from a critical standpoint, it's usually hit and miss. Some celebrities have done poor jobs and had no business being there. While others have provided for some pretty entertaining segments and matches.
I don't really buy into celebrities having actual wrestling matches unless they're athletes. That's why Lawrence Taylor and Floyd Mayweather IMO were two of the greatest uses of a celebrity ever. Both drew in huge fans and ppv buys (isn't Wrestlemania 24 like the 2nd highest grossing even in wrestling history?), but both also did very well in the ring and put on some entertaining matches. Everyone shits on the Bigelow/Taylor match, but I think if you go back and watch the whole event, other than HBK/Diesel, it was the best match on the card. Of course that shows how sad the state of the WWF was back then, but it was still an entertaining bout. And Big Show/Mayweather was a phenomenal match for it's kind. Those guys could be taken seriously as legitimate wrestlers because of their backgrounds. Now Mayweather against Big Show was a pretty big mismatch upon first viewing, but we're talking about arguably the best boxer in the world. He's going to be a legitimate threat to anyone (if not beat everyone).
Mike Tyson though may have been the greatest use of a celebrity of all-time. He was perfect as the foil in the HBK/Austin matchup that kicked off the "Attitude Era" in 1998. Mike Tyson was perfect for that culture and period, as he was all about controversy and notoriety. He fit in perfect. And he's a lifelong fan so you know he knew what he was doing. He played a great heel with D-X only to turn on them and bring extra attention to Stone Cold and the WWF at the end of the match. At the time he was one of the biggest celebrities on the planet, so that's why everyone was "watching" when him and Austin got into on Raw. It was a huge moment, and everyone in pop culture was talking about it at the time. It was huge. And Mike Tyson's involvement played a major part in kick-starting the Attitude Era. Wrestling was getting hot at that point, but Tyson's involvement is what brought in so many new fans who were intrigued. Luckily the WWF was great enough at the time to provide such a compelling product that one Tyson was gone, the new fans he brought in stayed and watched. That right there is the perfect case and the template that all wrestling companies should follow and use if they're ever trying to get the most out of a celebrity involvement.
Mr. T at Wrestlemania was similar. But I think Cyndi Lauper played as much if not more of a role in kicking off the '80s boom period for the WWF. Tyson (as far as celebrities go here) acted alone in getting the WWF extra notoriety and attention.
In addition to celebrities who wrestle/and or get involved in the main event, I think there have been celebrities who have been very entertaining in more minor roles. The two that come to mind are Bob Uecker and Pete Rose. Both guys are so charismatic (especially Uecker) that he was perfect for the show. He's funny as hell (just watch the Major League movies if you don't believe me) and added some great entertainment to the Wrestlemania shows, but he didn't take away from them either. He just served as an announcer and interviewer. And he obviously did well at commentating considering he's a lifelong baseball announcer, so he knows how to announce obviously. And the scene where Andre choked him in the backstage area is one of the classic moments of Wrestlemania IV. Bob Ucker was used very well. Pete Rose is another one that was great. To me, his promo on the Boston crowd and subsequent Tombstone piledriver courtesey of Kane was one of the most memorable moments of Wrestlemania XIV and also got some mainstream notoriety as well. And his appearances in the two following Wrestlemanias were great too. He didn't get focused on too much, played his part did it well, and added some good entertainment to the shows. Those are celebrities that did well and were used right.
However not all celebrities have done well. Jay Leno is a great example. Now from a ratings and mainstream attention standpoint he was brilliant. I mean he's the host of the Tonight Show, he's one of the top entertainers in American entertainment. Everyone knows Jay Leno, so him getting involved was a major coup and he did his job of bringing in ratings, ppv buys and getting WCW mainstream coverage. But obviously his match was horrible and it made WCW look terrible. This was a case where he should've probably managed DDP and maybe got a slap in on Hogan at the end or something. That could've worked. The angle was good, the apperances on the real Tonight Show and on WCW's mock Tonight Show were good. The match though was horrible.
Wrestlemania 2 was another great example of celebrities that just downright did a horrible job and had no business being there. Joan Rivers and Lynn St. James commentating was some of the worst commentating in the history of the business. It was horrible. Ray Charles opening the show was brilliant (then again Ray Charles could fart for 3 minutes straight and it would be masterful, one of the greatest musicians ever, but that's another topic for another day), and the football players in the Battle Royal did well. But the worst example of a celebrity involvement is when you give them something to do that they can't handle.
And obviously some of these guest hosts over the last year have been downright horrific. I've seen some of the most lame, boring, horrible segments ever put on a wrestling show. However, some of the guest hosts have been good. I enjoyed this past Monday night, the guy from Royal Pains (can't remember his name). He had good enthusiasm, didn't try to act as though he's a legitimate tough guy wrestler when clearly he isn't. He acted like a total wimp, which is what he is, so his match wasn't poorly portrayed. We all knew it would be the Big Show doing the majority of the work and they played it like that. And it didn't take away from the show too much. And the guy was funny. He was an example of a good host. Shaquille O'Neal I thought did outstanding. I was actually excited at the end of the show to see a showdown between him and the Big Show. I actually really hope that when Shaq retires, Big Show is still around so that WWE can have a Shaq/Big Show match. That would draw in ratings and buyrates galore, and dare I say I think it could be a good match for it's style (two giants/big guys). Shaq is an athlete and is a lifelong wrestling fan, so I'm sure he would take it serious, train hard and want to have a good match. And Show has a great track record of having successful ventures with celebrities in wrestling (not counting the atrocious sumo match with Akebano and Wrestlemania 22. Hey, we all can't have perfect track records).
Anyways, overall it's important to continue to have celebrities involved with wrestling. But in order for it to be a complete success you have to give the celebrity a role they're suited for. When you put someone like David Arquette or Kevin Federline and have them go over on world champion wrestlers, that not only looks stupid to wrestling fans, but it looks stupid to non-wrestling fans too. No one on the planet can truthfully see a guy like Kevin Federline beating a guy like John Cena in a "fight" (staged or not). So when you have scrawny wimpy celebrities beating trained professional athletes that makes wrestling look like a joke which is exactly what a wrestling promotor shouldn't want. When your celebrity and booking of the celebrity makes wrestling out to be a farce and joke, then you've failed at using your celebrity properly. At least when Lawrence Taylor beat Bam Bam Bigelow or when Floyd Mayweather beat Big Show or when Mike Tyson punched out Shawn Michaels anyone could buy those things happening because all three guys are legitimate athletes and tough guys. Those are sensibles stories.
So pretty much any celebrity that is popular at the time can draw in ratings and viewers. So from a commerical standpoint, it's easy to be successful. But to also put on good TV, the celebrity has to be used right. They have to be given a role they're suited for. As long as that happens, then everyone wins.