Again, I disagree. You can't point to history between Austin and Rock from 2003 then claim that Undertaker's history with Roman where Reigns gave him 1 of 2 losses at WM doesn't mean anything.
If we use your argument, Cena doesn't have anything to do with "this version" of The Rock, either. It's not about versions of characters. The history was there for Undertaker to want revenge on Reigns for his loss at WM. Stone Cold had nothing to do with the champion. Him showing up would have blown the roof off the building but made no sense. Taker at least makes a tiny bit of sense.
Of course I can, there is significant history between both characters, there is virtually no connection between this version of Roman, The Bloodline and Taker.
Cena has history with The Bloodline, so even if we take Hollywood Rock out of the picture it makes sense, particularly as The Rock is more of a hybrid character that leans more Hollywood, Roman is a completely and totally different character from the failed "believe that" face run train wreck from that time period.
The fact of the matter is neither of them showing up in this situation is logical, but Austin sure as hell would have been the better choice for a cheap, short sighted pop and superior WrestleMania moment.
We're going to simply have to agree to strongly disagree on the matter, otherwise we're going to continue to go around in circles.