She's so shit rn, but I don't think that relates to her powerwise.
Simply put, why play this champ
for a strong level 3 gank and a hard dip late game, when you can play:

All of these can gank/counter gank level 3, sure some may not be as reliably effective as her in the gank (just eve really, maybe skarner) but they get the job done, transition all into the mid game, and one shot/tank up the late game.
If you're fed on Elise, you can't make use of the advantage besides picks, and if you're behind your dead weight. She's like the pantheon of the jungle, except before the W nerfs you had the option to go off tank and be useful or counterbuild your opponent.. but with the base damage nerfs that option is no longer available.
Also the AP itemization changes hurt her more then helped her. What was really good was rushing old
for pen, and then upgrading it into % current health burn for 1600 gold... now you can only go
which only upgrades into grevious wounds you more often then not won't need, and that also delays other power spike items should you decide to sit on the orb just for the pen and upgrade later.
She loses easy access to pen and has to rely on her scaling off other AP items, and she doesn't scale well at all.
She needs a base damage buff on volatile spiderling; so she can have versatile build options again without gimping herself for going tank or utility.
or one of these effects that i'd welcome (take numbers lightly i didn't think this through):
Human Q: lowers the targets MR by a small ammount (5/10/15/20/25?) fixing her lack of good magic pen item now.
And/or
Spider Q: Refunds part of its cooldown (20%/30%/40%/50%/60%?)on killing a large monster or champion. Speeding up her clear/teamfighting a bit, I wouldn't mind it working for minions either so laning is possible.