Above all, we really need a new rework of the old girls to rebalance everything. RG is only good for a few 5* (well, only Poison Berry is actually really good) and most of the old 6* are worse than the new event 5* RG. There is no point at all in * ranking now.
Actually, only abilities really matters now. Stats, FM, equipements are close to nothing. Even ampule, centies, skill level and affection are secondary. I mean, did you even bother to get all your support girls to lvl120, full high amp and lvl5 skill? I usually don't. I only focus on attackers. Supports can do their support job at lvl80 with regular ampules. And it change almost nothing.
That's just sad. The game is rich with a lot of different mechanics and stuff with infinite potential but everything is crushed under the ability powercreep.