The Rock is obviously one of the greatest ever in terms of pure charisma and just being a star. His promo's in the attitude era were perfect for the time.
As tubby has said though when he came back and did the same schtick, it seemed outdated and stupid. However I don't blame anything of that on the man, as basically anything he does or says normally as Dwayne Johnson comes across as more charasmatic than most people in showbiz, nevermind wrestling. And given prior form, I think it is fair to but the blame at WWE writings door on them (even if it was them just telling him to do the classics except PG)
Punk is absolutely one of the best ever on the mic as well, always has been someone to grab your attention and be incredibly compelling whether face or heel. Even disgarding both nostalgia and modern bias, he is an all timer on the mic.
MJF is great for his age, but maybe he does take too low a shots, although I definitely feel that's the gimmick (tacky rich boy who think's he's a bigger deal than he is). I genuinely think it's deliberate because when he brings the fire and not the jokes, and the way he reacts, are signs of someone who really knows what he is doing. It's still scary to think this dude is 24, you've got 15-20 years mega heel with this guy.