Thoughts on How Mid-Season Updates Will Go (Champs and Rift)

So with the small teaser being released we get a small look at the reworked Zac, Sej, Maokai and the new Rift Herald. Now I won't go into full detail about it all (go to the link and read for yourself) but to give a brief summary of what I can tell/know:

Maokai ult now is like a Nami ult but slower and roots enemies + saplings deal more damage when in bushes and os more resiliant to burst champs (I believe)

Zac's ult now will allow him to possibly fling entire teams in a certain direction (if not a few champs) and turns out that leak was right about the slamming two targets with his new Q now.

Sej can freeze enemies like Braum but attacking them will deal also deal a crap ton of damage her old W is now more of a skillshot instead of enhanced AA plus small DoT circle (like Garen or Shyv) and her ult seems to have changed a bit.

Finally, rift herald now takes an inventory slot allowing you enhanced baron recall but also allowing you to launch her into a lane and help push it!

What are your thoughts on this? How do you feel mid-season will go?