You'll have to point out this whole "Saitama has no limiter" page to me. I remember something about him saying he'd transcended his limits or the limits of "normal" strength or whatever, but nothing about him having no upper limits on how strong he can become or whatever.
And even if that were so, potential doesn't mean shit if it's not realized. You might as well say Gohan is the strongest character ever because he has the most raw ki potential of anyone in DB, even though he never trains or makes anything of it.
If we're gonna talk about this seriously, we have to talk about what have we actually seen him do, and thus far, he hasn't done ANYTHING that suggest his power or even his power potential trumps any and all anime characters.