What a fascinating thought and one that's never occurred to me. Now it has I'm struggling to think of anyone better in that specific regard.
Each of the mega-greats had no inclination to do certain elements of the game (often defensively) but in Rooney you had someone capable of everything. Speak to any of the Man United squad who played with him and they all say he could have played in any position and been outstanding (he was even, apparently, an unbelievable goalkeeper).
He could score all types. Tap-ins, headers, left foot, right foot, piledrivers, lobs, dinks, passed-finishes etc. He could run. He could tackle. He had timing and positioning. He had awareness. He was unselfish but still put up huge numbers himself. Passing was outstanding too. He had physicality and dynamism but was also cute when needed. Set pieces were strong. Goodness he was good.
Even with Pele, Messi, CR7, R9 etc. you can find elements of those which they lacked or had little desire to do.
Maybe Maradona comes closest although his size would have precluded him from winning aerial duals in the way Rooney did.
From what I've been told - although he was well before most of our times - Alfredo Di Stefano might be close too?
Others I can think of who possibly could have done it but maybe weren't given the chance in the very advanced positions:
Steven Gerrard
Yaya Touré
Ruud Gullit
Clarence Seedorf
Franz Beckenbauer?
Lothar Matthäus
Sergio Ramos has defended outstandingly and scored in mad numbers, although I dunno if he's a great footballer?
I suspect one day we'll be talking about Eduardo Camavinga in this conversation.
I'm told Martin Peters was ludicrous in multiple positions.
Jude Bellingham?
As an aside, after writing the above I just googled it and this bit of interesting silliness came up...
https://medium.com/@strijdhagen/the-...l-5a11fdb9f51d