Mind Control is great for grabbing a wounded straggler from a retreating team or walking an over-aggressive player into your team/forts. It's a little harder to grab a backline hero like Morales or Li-Ming safely. It's a great ult though, she definitely has two viable ults now.
Her build diversity sucks though. Like I net more siege damage with two Black Arrow talents at 1 and 7 with Paralysis and Unstable Poison than I do with Withering Fire siege damage oriented talents from 1-7 with Overflowing Quiver, Withering Barrage and Barbed Arrow. Mercenary Queen looks awful so that pretty much leaves one viable talent at level 1, two viable talents at level 4 and maybe one talent at 7. Possession might be fun to take laning with a Xul or Zagara but it doesn't really look worthwhile. Level 13 is always Will of the Forsaken for me, it gets out of so much CC. 16 is almost all teamfight/hero-centric abilities and one survivability talent.
It doesn't feel like there's a siege damage Sylvanas and more teamfight-y Sylvanas, just this awkward mash-up of assassin and specialist. I guess she's always been that but the specialist part feels worse now. And it feels like she has less build diversity compared to before.
I've been rolling with Paralysis, With The Wind, Unstable Poison, mostly just been using MC because it's new, Will of the Forsaken, 16 is kinda open, and usually second tier of MC.