**I've edited this to update my opinion after playing games on him.
Firstly, I think his knew ultimate and Q are really neat and while I'm glad they're being added to my favorite champion, I'm really concerned about a couple things. Mostly Zac losing way too many numbers. On live, Zac can put out a very good amount of damage. Taking away Zac's main source of blob generation and sustained damage (live ultimate) is already damaging. You really cannot justify gutting his damage like this. He seems like much more of a "one pump chump" than ever before, but with greatly less burst and sustained damage (and lockdown on top of which).
1) I don't think a questionable replacement for Zac's ultimate and a fun yet dinky Q utility upgrade warrants nuking all of his base numbers. Taking 10/20/30/40 damage and half the knockup duration on his jump is fucking **brutal**. Definitely want to see that knockup duration restored to the full second and his ultimate channel up to 1.5/2s. It's more aligned with less ultimate reliance which is what you guys were going for.
2) His Q autoattack doesn't feel right without his autoattack physical damage being applied, as well. Feels really weak especially when clearing camps when you're focused on dealing damage for the most part.
3) His walking animation is far too derpy while he's under 380 MS. https://www.youtube.com/watch?v=yWAN6Q3o2bM&feature=youtu.be (example)
4) You can no longer E+Flash, which brings a lot of his skill cap and clutch playmaking ability down. Really important this comes back.
I'd say number 2 is the least important, but if all things could be fixed that would be pretty awesome.
if any rioters want to talk 1 on 1, i acquired rank 1 in NA with zac last year and have been challenger for 3 seasons. my ign on live servers are Silas and SWKM.