I think rek'sai ult need another rework.

Her ult doesn't fit on what she should do, she's suppose to be a diver (with someone play her as a tank) but her ult call are better for assasination target. As a fighter her role should be suppose to stick around target and deal massive sustained damage but her ult is feeling a lot as burst. Another issue that i found is what happen after she ulted. Let's suppose both scenario, she killed her target or her target survive. If she kill her target, she has to walk to other target which require time letting her up to be kited as hell (she could use W and E but it would still require a lot of time and it's a lot predictable and slow). If she didn't kill her target, she fell her next auto a bit confused (it's a bit too hard to use Q after that jump animation since it put her a bit far from her target, resulting her to be a bit clucky).

I fell like a diver rek'sai should get a ult similar to but work a bit different. Vi ult deal damage to all target in her direction and knock them away and provide a point an click CC. Rek'sai instead still need to land her Q or attack her opponent for use it digging the terrain above him to reach his opponent (basically a better E and W) but it should be :

A) An aoe CC with a fury generation based on how much target he hit (max 3 so he has to land at least 1 auto to get his E true damage).

B) A damage reduction ability (maybe that scale with AD so she should be build more like a fighter) to help her after she goes into the battle (3 s i think is enough) to deal the right amount of damage (CC is apply only on the ulted target).

I thinked about the option A for he player that loved to play her like a tank (CC on multiple target) and the option B for the player that like to play her a bit more agressive (the option B also fit better with the diver class). i don't think that both solution should be apply since it would turn her in a overloaded monster but i think that's both of the solution are way better than the current one.

For compensating this the ult damage would be a lot lower since she got a spell that help her with her kit. It could be a 100% hit spell or a dodjable one so you won't get CC and damage like it alredy work (maybe under your feet the ground would be a bit different for letting you know that she will come in that point). The animation should help her to land/use her Q since the actual one is a jump that create a lot of akward situation (for an example after you jump, you would fell a bit disoriented because the target can still move before your jump so you would lose a bit your position). The animation shouldn't be so hard to implement because half of her animation is alredy on her ult (bury animation). In the case A, i would like to see her smashing out the dirt and the rock (Just the animation effect) in the case B, i would like to see her body covered with Rock or Dirt to fit her Damage reduction aspect as a visual effect.