Once doflamingo and katakuri actually come back to the main story i wonder if people are gonna say their hype and strength is a retcon
It is retcons to the left and right but it is what it is.
With Jinbei (1.1), Boa (1.6), Croc (1.9), Mihawk (3.5) we can safely assume at least Kuma (~2.2) & Doffy (~2.5).
Kuma and Doffy who were originally the highest might even be higher because they both know everything about Vegapunk, the underground dealings, the secrets of Mariejois, the tenryubitoo and so on.
Moria 0.8 just going by strength and inflation but he is very cunning and dangerous too so he might come back with some seriously OP dead characters and thus be 2+ as well completing the return of the ~300-million trio of Shichibukais.
My heart does go out a bit for my man Jinbei being so far below his fellow shichibukai even though he showed during marineford that he could hang real well.
Katakuri never lost to Luffy, he gave up for the greater good of humanity or something like that. He probably did see some interesting future far ahead and thus took an L on purpose.
Edit: Forgot about Law, Buggy, BB and Weevil there for a moment. I suppose if Moria gets at least 1B it means all shichi are 1+, some of them close to 4. That's truly a third world power if they collaborate. Only question mark is Weevil but he will probably be around 3.2-3.7 as well. Man is supposed to be undestroyable.