I'm getting to that point with equipment as well, especially with the counter girls since you really want to dress them up in the best defence equip for those big counter hits.
I'm currently lvling:
4 x 6* girls (2 hit and 2 slice, lvl 68, 63, 38 and 21 with the last 2 needing evo)
25 x 5* girls (3 slice, 6 hit {5 need evo}, 7 Pierce {5 need evo} and 9 magic {4 need evo})
And I still have 68 ampy's to use on my 6* girls.... so much gold needed for that.
When I have spare manyu and gold I lvl the 2-4* girls as well for nation battles and completion so for me even with no new girls I have a lot of play time left in this game and I do like that.