Rek'sai feed back

Rek'Sai has problems.

The biggest one is no sticking power. She only gets MS while underground, and it's not enough MS to go underground and come back up again to attack to be useful for chasing (similar to how Udyr uses bear form) .

She has kind-of weak base damages, but good scaling. However, there is no way to take advantage of the good scaling because she doesn't have enough durability built into her kit so she has to build it in items. (the light sustain is enough to make up for it)

Her ult is cool and all, but it's nearly impossible to use effectually late game (and by no means easy early game) because it's difficult to keep tunnels up in places where you might want to gank. Typically, if the enemy is close enough to a tunnel for your ult to be useful, they're close enough to get rid of the tunnel before your ult finishes.

I'm not saying she should have all of these things fixed but I do think these are some things that hold her back from feeling as good she could.