People tend to forget that these people are actors, and play a special role in their company. And when it's time for that actor to move on, so should we. It saddens me to think anyone is still caught up with a wrestler's name (of all things) because WWE changed it. No other career in drama has it's fanbase bitch and moan that "Hannibal Lecter" is playing "Odin" in this role now; chalk it up to people not knowing how to let things go.
There is a slight difference in the situations though that while an interesting idea to compare, cause it to deflate in reality.
It's not Hannical Lecter playing Odin, it's Anthony Hopkins playing both. You wouldn't want to watch a movie where the character was the same, but they used the actor's real name instead of the one created for the character.
In wrestling, the character and the name are what becomes most associated together with the audience and it is the character names that are used to sell the product. For actors, it's often the ACTOR who'se name is used to sell the product. It is promoted as 'Anthony Hopkins Is Odin in THOR' not 'Odin as shown by Anthony Hopkins'. The difference is slight but it does have an impact and reverberance in the minds of the audience. I don't care one iota what Phil Brooks does in his personal life, but I love watching CM Punk kick ass in the ring.
At Mania, I want to see the dark and brooding, sinister Undertaker demolish his opponents, not watch Mark Calloway pretend to beat up on some guy. The role is more important in wrestling then the reality.
So if they started calling HHH by JP Levesque, it wouldn't resonate with the fans the same way. So sometimes they need to change names to have an increase in the interest and reactions by the fans. And other times, it's simply because of copyright/ownership issues. WWE wants to own the names and persona's of all their players so that they can market them even if and when those people no longer work for WWE.
Bringing in outside guys and renaming them has been a tradtion in wrestling as old as the headlock, going to the very start of the sport and running through the territories and into the modern era. I have no problem with renaming and packaging guys when they join your company, because that is the role they are taking on(going back to the actor comparison). You wouldn't have Odin renamed to Hannibal just because both are portrayed by Anthony Hopkins so why worry about an indy guy coming in and being given a new name to fit his potential role with the company.