Who is the one roger is waiting for and who is the one of legends?
What has Oda written if not straight forward and predictable on stuff like this? I think you may just be indulging wishful thinking.
If the story is not going for "HE IS THE CHOSEN ONE! IT'S HIS FATE, HIS BIRTHRIGHT!" is indulging wishful thinking, so be it, I'd rather hope for one piece to surprise me like it always does then using a cliche and safe narrative everyone predicted a while ago.
Roger might be waiting for someone like luffy, but does that mean luffy should also be the chosen one of old legends?
We need to think outside the box a little
"what if it's actually about Robin"
"WHO is blackbeard? what's his real past"
"what about Momo in all this"
"what did joyboy promise" "what about the ship in fishman island"
I don't know!!! no one knows but Oda (and maybe Greg to some extent) but im sure as hell it's not some predictable plotline any amateur can write