I personally hate the way her rappel is currently setup. The offensive buff you get from using it is screwing up her ability to be balanced into a good champion. They need to gut the stupid damage buff she gets from using it and throw in some damage to compensate into her regular spider form. Instead what they should do is throw in a DEFENSIVE boost that actually makes a difference. The healing boost on auto attacks is almost nothing. Given the fact that in a lot of situations she can't use rappel to escape she needs a defensive buff when coming down from rappel and a not just a little one, a huge one in her current state. Forget about building any offensive items if you're jungling her because you're going to get blown to hell before you can do much with them. A character with the limited amount of CC that she has is either supposed to be very damaging or very tanky and she is neither. She needs fixes badly.
It seems like she has 3 forms almost. Human form, spider form, and then spider form after rappel and W activated. Can we get her spider form a little more fluid considering the fact that you're already managing human and spider.
IMO she should automatically generate spiderlings after a very short amount of time either that or have her be able to generate them while in spider form. Who is going to switch out to human form because you lost all your spiderlings. Her human form could use some type of mobility. One possible change without a huge rework would be giving her W the option to teleport to that spider in spider form and explode it, the damn thing moves the speed of slow, has a high cd, and doesn't do much damage to begin with. Everyone maxes it last how about we give it some utility other than vision like most abilities which are maxed last. Instead they did the opposite and made E even more important to level up so maxing W last is almost gauranteed, meanwhile E (rappel) is the one ability that would be great if it didn't need to be leveled like it does.
Her W lasting 3 seconds is just annoying as crap. You generally get hit with some form of CC that ruins most if not all of that time to begin with. It's a garbage ability for her, in fact if they made that into something decent she might be strong enough with a change to that skill alone.
Spiders are supposed to set up webs and wait for you to walk into them to get you. Elise in almost no way resonates a spiders attributes. She certainly doesn't give off a vibe of feeding on her opponents, or lying in wait to trap them. She probably needs a rework TBH.