Chanwan
G.O.A.T.
Then I would state that he'd still be less deserving than at least some of the Slam winners, even though he himself wouldn't necessarily be undeserving.
I see your point, but I don't think it would be at least some slam winners.
As of now,
Djoko has 1 slam, 3 Masters, a slam RU, 5 finals in total and h2h vs. top-10 9-4
Rafa has 1 slam, a Masters, a slam RU, 7 finals in total and h2h vs. top-10 6-4
Fed has a Masters, a slam RU and 8 finals in total and a 12-4 h2h vs. top-10
Stan has a slam, a Masters, 3 finals in total and a 6-1 h2h vs. top-10
Cilic has a slam (obviously, neither Cilic nor Wawrinka are really in contention though)
If he were to become nr. 1, if he - at the very least - need a Masters and a WTF.
That would give him a WTF, two Masters, a slam RU and 10 (or more) finals in total, a possible DC (not that relevant, but everything counts here) and an unknown but dominant head vs. top-10 - say 19-6 or so.
You would still be able to make a case for Novak then (a slam and 3 Masters), but I can't see the case for neither Rafa, Stan or Cilic.
It would be a season with no dominant player, where Fed was the most consistent, got to the most finals, did the best vs. the top-10 and won the 5th biggest price.
Either way, I'm pretty sure Novak takes it, who's the only one with a fair claim to it as it stands right now.