Draktharr Evelynn in her current state is incredibly good. At least, that's how she's felt to me; like a real assassin, even, with a proper AD build.
Since her E does magic damage now, I fear AD Evelynn won't be as good any longer. Sure, she'll apply on-hit effects, but with the loss of her attack speed steroid, and a new reality where she'll do only magic damage, armour pen won't be worthwhile on her and opponents can more easily itemise against her.
I feel that as it currently stands, Evelynn loses build flexibility. Previously we could build AD if we faced heavy Anti-AP opposition, or wanted to tap into the assassination line of items. Now, it looks like the build path is more "solved" in that we buy whatever AP items are good for AP assassins. Since her Passive lost Mana recovery, we might also be locked into Runic Echoes to solve any mana issues she might have, unless they've loosened up on that. Since I haven't seen scalings numbers yet, it's still possible we'll get to tap into AD Evelynn as before.
I just fear she won't be as valid a choice as she is now. Certainly easier to balance, and it won't temper my love for her, but I would've loved to see that option intact.
I suppose I'm also a bit disappointed Evelynn went from being a champion that required strategic insight and less on the direct mechanics to a champion reliant on skillshots, but that's my inner Bronze scrub talking. This ought to at least allow us to express mastery better, though it looks like we'll still need to be as skilled at utilising our stealth as before.