Honestly speaking, she's not as picked as before. Considering that she do excel and broken with a player who can actually use her. Apparently, she's actually less effective as an assassin in later games. Aside from this, could be in relation to her skin release.
I think everything depends on the person skill's to use the fanny... I meet quite a lot of fanny users who got hyper like pro for suck like chicken. But only strong for fanny isn't enough, you still need a bunch of good teammates to support you! I don't use fanny either, very strenuous to learn and its takes a long long time to become a good fanny...
Because many pro fanny players don't play her in comparison to other assassins. The reason is she uses too much energy without the buff. Second, there is 1 jungle camp that gives her a buff.