He has gotten a decent amount of mic time and has done well with it. He isn't a humorous heel, he isn't an articulate heel like Jericho. He's a savage, a brutal beast of a man who does nothing more than get the job done his way. Not sure what you're expecting him to say when he's got the mic, but for what it's worth he has gotten the point across. He has a recognizable voice and style of speech that fit his look at motives very well.
He can't wrestle? Tell me, what exactly is that supposed to mean? Clearly the largest and most succesful wrestling company in the world thought he was good enough to give their most prestigious belt to. Of course there has been some less than deserving champions in WWE's storied history, but for the most part every champion had somethign about them that set them apart from the rest. The fact that he was given the belt too soon can be argued. I absolutely see why some didn't like the way that went down. He has done plenty since then to at least demonstrate that he is more than capable of hanging with the big boys.
It's funny that you talk about Cena or Batista's limited moveset, yet in the same sentence you praise Orton? I like Orton as much as the next guy, but seriously take a second look at any of his matches. He uses the same amount, maybe even less, moves than either of the other two men I mentioned. He has the RKO, that back on back neckbreaker, the stomps, the hangman ddt and the quick powerslam. Oh yes, don't forget the head lock. That's five moves right there and I gaurentee that any other moves you mention him performing are done rarely. Why is it a demonstration of a limited skill set for Cena, Batista and Sheamus yet Orton gets off clean for it? Sounds like a steaming pile of hypocrisy to me.
Maybe I wasn't paying attention while watching his matches, but he seems to get a damn good deal of heat. Credit needs to be given to Triple H as well because a lot of the heat comes from simply destroying a top face. He's done fine for himself in the heat department. He's still green and people are coming to terms with his character. Somebody like Sheamus, a no frills and no jokes bully always makes for a good heel. You pair that with decent mic skills and a tremendous look and you have something special.
I understand the type of heel character Sheamus is playing is far different than Chris Jericho (for example). You're right when you say he's portraying a beast, an animalistic kind of guy. He's getting it done his way, I got it. I just don't like HIM doing it. It's boring me to death. Other guys have taken on similiar characters (Brock Lesnar, Vader, Sid, etc), and I just don't find him nearly as believable. On the mic, he seems manufactured. I don't see a lick of natural acting ability in the guy. Is acting as important as in-ring ability? No. But this is entertainment, and I don't find him the least bit entertaining.
Did I find Vader, Sid, or Lesnar to be overly entertaining on the mic? No. But in the ring, those guys had a presence. A real physical presence. I just don't get that from him. He's a big guy, but he doesn't have nearly the physical, intimidating presence of a Sid or Lesnar. So I think when it comes to his character, I just don't buy into him doing it. Just a difference of opinion.
You're right, the biggest and best wrestling company in the world obviously see's something in him. And you're also right when you say that they have made mistakes before...and I think he's one of them. I guess I may be alone in this, but the guy hasn't impressed me in any match he's been in. Does he need to impress me? No, obviously not, I mean nothing. But it's my opinion that the guy hasn't impressed me in the ring. I think he's had the opportunity to work with some of the biggest and best guys in the business right now (Orton, Triple H, John Cena, etc.), and out of those matches, I can't recall a great performance. At least not a performance worthy of holding a World's title. It's not that I hate Sheamus as a professional wrestler, I just don't like him in the main event picture.
As for him winning the belt early on in his career, that really doesn't matter to me. I have always thought that if someone is talented enough to get a massive push right off the bat, I'm all for it. Sheamus has had the quickest main-event push I have seen in a long time, maybe ever, but that's not at all what bothers me. If they would have done this exact storyline with Brock Lesnar, I wouldn't have cared because I believe he is talented enough to warrant such a push. I don't feel the same way about Sheamus.
When it comes to Ortons moveset, I am not saying he has uses a lot more moves than Cena/Batista/Sheamus. For me, it comes down to execution. I don't know anyone, in professional wrestling today, that executes his regular moves with more aggression and intensity than Randy Orton. When it comes to Cena, Batista, and even Sheamus, I don't see them being equal to Orton in terms of execution. Wrestlers on the level of Orton, Batista and Cena often only use a limited number of moves, I know that. That's why, for me, it comes down to execution. And I really don't think it's in any way hypocritical of me to say Cena, Batista and/or Sheamus are not on Orton's level when it comes to that part of the game.
You are correct that he get's a good deal of heat, I'll give you that. But I think it has a lot more to do with, like you said, the guys he beats on. He has had the opportunity to start his Raw career off battling guys like Cena, Orton and HHH. The thing I wonder about from time to time is, what if he had started off (on Raw, not ECW), feuding with someone of a lower caliber? Someone like Kofi or Evan Bourne? Would he have gotten such a crazy amount of heat? I'm not so sure, but I won't speculate.
I guess what we really have here is a difference of opinion. You obviously like Sheamus, and I do not. Also, I do not think it is one bit hypocritical for me to feel the way I do about Sheamus (and his, what I view as, mediocre moveset). I just don't like the guy. Sure, he has some upside. In a few years, I may bite my tongue and become a fan. But as for now, I'm just not feelin' the guy.