Just my experiences in duel plus from what I've heard from a few gm/masters players and watching SamDaDude.
A few notes and opinions I must make clear:
The Mulan ranking is my estimate of where she'd be based on playing against her every casual conquest in solo.
Susano is overrated, Jing Wei is massively underrated. Anhur is a tad overrated imo. More people need to learn how to play Chronos. Morrigan straightup needs a nerf.
Hebo, nuff said.
Banned or picked, must be braindead to lose to anyone below S- with these gods.
Gods usually not banned but typically picked. Can carry you to masters.
Same as S but have a weakness or two
Must be a mechanical wizard at these to get them to masters, still viable anywhere with the right skill unless in a bad matchup. Usually take you to diamond
Cap out around diamond, but have a few gods they counter.
Your standard issue obscure picks. These gods shouldn't see the light of day in diamond.
Bad, good luck getting to plat with any of these.
Actual troll picks