Water is super reliant on debuffs, so according to debuff haters Water is in a really bad place for a long time. I think Water will be in "trouble" until Cthulhu and Shiva Awakenings, but those are still... uh 10 and 8 months away. Funnily enough, Azazel is between those two so have fun with that.
I don't fully agree with the debuff haters, but it is a true that specific content will be difficult for debuff reliant builds. The thing, this "specific content" just happens to be just about all very-endgame content.
I think that you're underestimating just how powerful Gaia's defensive options are (they are absolutely insane), but that kind of playstyle is not for everyone. Anyway, Titania and Cybele would be your Wind core and go in every fight, the other two would depend on content and how you like playing.