I dunno why ppl speculate about this. Persona always have these "complete" "enhanced" or whatever you want to call it editions, its gonna be Persona 5 with added characters, a bit of extra story events, an extra chapter after the end that you might need to play the game on new game + to get and so on. I think the only real mistery here is if its goinna release on Switch and/or Xbox as well or if it´ll stay exclusive to PS4.
Well for starters, these enhanced versions don't always come to the original system. Persona 4 Golden was handheld exclusive. P3 Portable also had a secondary female main character, and that didn't come to PS2 either.
So if there was going to be an enhanced version, people were wondering if it would only be for handheld, or if it would be on PS4 as well.
And we're also now in an age of DLC, so this could be an add-on purchase if you already own the original Persona 5.
Secondly, Atlus registered several P5 related domains, not just P5R. There was S, M and B as well.
We didn't know which one would be the enhanced version, if any. Turns out it's probably P5R.