Can I get some insight on how Kai'sa E is intended to be used before it's evolved?

At the moment, it's definitely the most confusing part of her kit. You get a decent AS buff (which feels really critical to use correctly, given her underwhelming AS/lvl and the need to proc your passive), but you lose DPS upfront for hitting your AS steroid because you're locked out of autos.

I'm not the smartest guy around, so some of this might be wrong or ignoring things, but a few thoughts on Kai'Sa's unevolved E:

• It feels awkward, like I'm making a tradeoff no other ADC makes without gaining a more substantial benefit in exchange. (E.G., Twitch gets a very long stealth from his steroid button and gains lots of assassination potential in exchange for it not being an upfront steroid; Vayne's reposition grants bonus damage on your next auto and is an AA reset...)

• It's really hard to use it to react to engages or being engaged on (and this is most relevant in lane). E.G., you kinda want to DPS down whoever your Leona just rooted while they're rooted, but if I want my AS steroid upfront, I have to give up a huge chunk of time that I might be able to hit them without retaliation just to get my AS steroid up. Likewise, if I'm trying to trade back on someone engaging on me, needing to wait over a second for an AS steroid to help trade back is... underwhelming. (I understand that, say, Twitch has this problem too -- but Twitch's stealth is substantially better than Kai'sa's E in terms of kit synergy. He also -has stealth- at low levels.) And this all feels triply bad because I want the AS buff to help proc my passive. Even in the champion's most obvious setups for success early on (thresh hooks and flays, leona lands e), the way her E works feels like a detriment to coming out ahead because you're doing doing literally nothing for at least solid second if you hit it, except being Sonic. I just... don't get it.

• Are you supposed to E before you ult? After you ult...? If I'm trying to duel someone down, just zooming around for a second and not dealing any damage is a good way to lose the duel -- but at the same time, hitting E sure telegraphs that you want to go in and is a giant red flag for the other guy to back off. You don't even have something really threatening to do with the burst of mobility either (in the way that blitz zooming up is scary because he can hook you from range). This is sort of an extension of the problem above: it feels like there's no time to hit the button that feels good until it's evolved because you stop doing damage, and no amount of bonus AS makes up for the fact you probably just lost an AA in the DPS war against the opposing lane (who can usually just hit their steroid without penalty). It's only felt good to use unevolved when... (see next)

• The main successful use case I've seen is the following: 1) Someone gets CC'd, 2) you zoom into range to hit R, 3) you hit R and kill them. This is ostensibly how her kit is supposed to work, because everything works wonderfully in harmony, but it's also very team-reliant. I guess the other desirable case is something like 1) hit E to dodge a hook/bind/etc., 2) hit their face hard, but this is kinda difficult to force given her low range, lack of CC, difficulty disengaging if things go wrong, and the fact you just spent a lot of the mobility you'd want to use to go in on dodging something.

• This is kind of tangential, but the need to evolve E locks her boots slot in an insanely painful way. As a 500 range champion, she's a natural lock for tabi or mercs to not die, but unless you buy zerker's, you're not evolving E for a pretty damn long time, if at all, on many otherwise logical builds. (RFC+Shiv+AS/lvl is not enough to evolve E. Hurricane+RFC+AS/lvl is only enough to evolve E at level 18. And so on.)

In general, I'm assuming I'm undervaluing it as a reposition/tool to dodge skillshots, but I also can't think of any other ADC reposition that locks you out of autos for so long while leaving you so vulnerable. The skill really doesn't make much sense until it's evolved, and I can't help but think it's a large part of why she feels so bad. = /

Any insights on what the skill is supposed to do that I'm missing here? It's almost to the point where I wonder why it doesn't have stealth at baseline, because the skill seems to be balanced the way it is because being able to act during stealth would be busted... but it has those same drawbacks even before it has the stealth. It just feels bad.

EDIT: It's probably also worth comparing Kai'sa E to MF W, which also gives a lot of movespeed and an AS steroid... but gives them both for four seconds without a lockout on autos first. While I admit that MF's kit is vastly different from Kai'Sa's, Kai'Sa's kit doesn't seem sufficiently loaded elsewhere to merit the stark power contrast between the two abilities (imo).