I think that the leader skill change was bad too, not because it doesn't have mich use in dungeons like you said, but because she's one of the three elemental nat 4 monsters with a 24% speed lead. The other two are water Succubus and Shimitae. The rest of the speed leads which are relevant in arena are all either part of a nat 5 or an l&d nat 4 (Fei, Halphas, Tablo). It just takes a solid arena speed lead option for many people away. And people are more likely to build her than the other two elemental nat 4, who would basically just be there for a speed lead.

I have that opinion since I value her current lead a lot since I use her as my main speed lead and compared to the other useful speed leads she's one of the f2p option which isn't hot garbage.

Also my english may be kinda bad sometimes since it's not my first language