My view is that the potential headliners for the next five or so years are as follows:
Randy Savage
Sting
The Undertaker
The Rock
Triple H
Vince McMahon
Kurt Angle
D-Generation X
Chris Jericho
If we're only going 5 years then those guys above can't all headline. And some of them I could see as being secondary headliners (ala Roddy Piper, Mr. Perfect, Eddie Guerrero, Ricky Steamboat, Mick Foley in previous years).
Other people have mentioned the Big Show, Kane, Kevin Nash, JBL etc. and to me those guys are secondary headliners, so I definitely don't view those guys as being headliners.
Obviously trying to predict the HOF classes are a crapshoot at best, but if I'm gonna take a stab at it, here's how I see the next 5 years going....
2015 Wrestlemania 31 (Santa Clara, CA)
Headliner: Randy Savage
Co-Headliner: Sting
After some thinking, I think these two are the leading candidates to headline next year's class. Randy Savage is the last major, headliner-level snub of the HOF. Of all the potential headliners that had issues with Vince, Savage is the last one remaining to get the induction. Obviously since his death (and even a little bit before his death), the company's viewpoint on Savage has warmed up tremendously. They've done action figures, video games, DVD's and other merchandise on Savage, and he's been promoted with their lists among other things. Plus Savage has a big time DVD with a documentary coming out later this year, and if it's a big hit (which I suspect it will be), WWE will want to capitalize on it, with him an induction. Not to mention it will make the fans ecstatic and can finally make the HOF seem more legitimate.
I actually wasn't going to originally put Sting as a co-headliner, because it appears he wants to be more active than just doing appearances, and wants to wrestle a bit. But in looking at all of the years ahead, no other year makes more sense to induct him than now. I can see him getting the Ric Flair treatment, in getting a HOF induction and then a final match at Wrestlemania. I think it really all depends on if a Taker/Sting match happens. If it does, I can see WWE holding off on Sting until the following year and inducting both together (Taker will be my headliner for WM 32 which I'll get to). But at the same time, the following year will be in Dallas, so I can see WWE going with a Texas themed class, and Sting doesn't really fit in there.
The other possibility is that these two get flipped around in their spots. Mainly due to Savage not being alive and there to make a speech. That's Savage's biggest obstacle as to why he may not headline, because no headliner for a class has ever been deceased. But with Sting going in as well, Sting can be the major name inductee that can entertain the fans and make them happy by being there. I just have a hard time thinking Vince will have Sting headline a class beings he never wrestled for WWE. Of all the major headlining inductees, Dusty Rhodes probably had the least vital WWE career, but even he had a good, memorable run there.
So ultimately I'm going with Savage as the main headliner and Sting as the co-headliner, though they could be flipped. I definitely see this finally being Savage's year. Though I've said that every year for the last 3-4 years, so..lol.
2016 Wrestlemania 32 (Dallas, TX)
Headliner: The Undertaker
Co-headliner: JBL
Honestly I do not feel that JBL is worthy of being a secondary headliner, let alone the main headliner, but WWE obviously feels different and beings this class will be in Texas, I can see WWE going with a Texas theme. Taker I think will headline as he hasn't officially retired yet, and there's a bit of a possibility that he has one more match which would be at Wrestlemania 31. By Wrestlemania 32, I think it will be official that Taker is done, and obviously he's going in at the first class he's available for. And with the event being in Texas, and in a stadium that could break the Wrestlemania III record, what better time to induct Taker then at Wrestlemania 32?
As for JBL, again, I don't feel he should be a secondary headliner, but WWE sees him in a much bigger light, and when it comes to their headliners for each class, they always want WWE guys. Realistically speaking, Stan Hansen or Bruiser Brody should be secondary headliners, but the younger generation of fans won't know who they are, and both had very small runs in WWE in the 70's, and that's it. I could see one or both of them going in that class, but not as the secondary headliner. Because JBL was a big-time WWE star, he'll get the nod. And beings he's from Texas, there you go.
For that class I would love to see Taker, Hansen, Brody, Freebirds, JBL, Dr. Death Steve Williams, and Paul Boesch (legendary Houston promoter) or Gary Hart as the non-wrestler inductee. That'd be one helluva class.
2017 Wrestlemania 33
Headliner: The Rock
Co-headliner: Batista
At this point it will really be a crap-shoot, because we don't know yet where these Wrestlemanias will be, nor will we know what relationships between the wrestlers and WWE will be bad and good.
I liked the idea of someone putting the Rock for Wrestlemania 35, as it'll be one of the anniversary Wrestlemanias, which will need a truly huge name. However I think I've got a better idea for who that spot will go to. So I think at this point with Savage, Sting, and Taker in the HOF, the next major star, chronologically speaking is the Rock. I highly doubt the Rock is going in next year, beings he's gonna be busy with the Fast 7 promoting among other things, and I also don't see him going in the WM 32 class in Texas, especially when Taker is right there waiting for an induction and makes far more sense to induct in Texas than the Rock. So I think by 2017, the Rock will have wrestled his remaining matches, and maybe will have a break in his movie schedule to where he could come and do the induction.
In that same token, for the co-headliner, why not induct another major wrestler-turned movie star in Batista? If Batista's career gets red hot in the next few years (which he's well on his way), then that will make a major induction even more worthwhile. Batista may not want to play second fiddle to the Rock, but it would make sense to induct him. By 2017, Batista will be in his late 40's, so his wrestling career should be winding down, which would be the perfect time to induct him.
2018 Wrestlemania 34
Headliner: Triple H
Co-Headliner: Chris Jericho
I think by this point Triple H will most likely be in the office full-time, and his in-ring career will be largely over (maybe a match or two a year, like Taker in the last 5 years). So I think that will be the time to do it.
And I also think by that point Jericho will also be ready to go in, he'll also be in his late 40's, so his in-ring career will probably be mostly over as well.
2019 Wrestlemania 35
Headliner: Vince McMahon
Co-headliner: D-Generation X
This year's class will be the McMahon-class so to speak. With WWE needing a big-time name for the 35th Wrestlemania, and with my timeline Taker, Triple H, and the Rock already being in, naturally it should be Vince. With Vince getting older, obviously we don't know where will Vince will be by 2019, he may be in declining health, possibly deceased. Or he may be just as strong as ever and still running the show. But I think by this point, Vince will be largely out of the picture, whether by retirement, bad health, or death. And once he's done, there's no one (not even Taker, Rock, etc.) that's more deserving of being inducted in the WWE HOF than Vincent Kennedy McMahon.
To keep with the McMahon theme, Triple H and HBK (probably two of Vince's favorites ever) will get their second inductions with D-X. Triple H supposedly wants to go in on his own first, before D-X goes in, so with Triple H getting inducted the year before, D-X would be ready to go. Plus, if Vince happens to have passed away by then, the HOF will need a major co-headliner that can take away from the sadness of Vince not being there (like Sting should do for Savage in 2015).
2020 Wrestlemania 36
Headliner: Kurt Angle
Co-Headliner: Kane
By this point both of the above guys will have been long retired, (maybe Kane will be in politics by then), but I think the headlining spots in the previous years will be too crowded for them to get the nod. With my timeline, by 2020, The Rock, Taker, Triple H, D-X, Savage, McMahon, etc. will all be in, which will then make room for your Kurt Angles, Rey Mysterios, Big Shows, Kanes, etc. I think Rey Mysterio is gonna turn into one of those political-related snubs and thus it will be awhile before he goes in. Big Show is also obviously a possibility, but I think Angle and Kane will go in before Big Show. Just a hunch.
John Cena, Randy Orton, Daniel Bryan, etc I believe will still be wrestling in 2020, so I don't see them going in yet at that point.
That's my take on it.