Unpopular opinion here : I'm actually convinced that
is the best character at the highest level of play.
His match-up spread against the top tier is just too good, beating soundly
/
/
/
/
& going at least even with the rest, except
(which is his hardest match-up I believe).
He can have some trouble with obscure characters such as
, but nothing too bad at all actually.
As the metagame progresses, anything below top tier is becoming less & less relevant. Diddy benefits a lot from this.
However, your definition of best character / #1 on the tier list can differ from mine.
If you think the best character is the character that can easily dispose of mid to high level players and net you a good placing, then yeah, that would be Bayonetta, followed by Cloud.