> Not to mention that WindowServer seems to take 100+% cpu since the upgrade

That's because some app is spamming window updates.

It's been an ongoing problem for many releases. AFAICT, WindowServer 100% CPU is a symptom, not a cause.

But apps shouldn't be able to hammer WindowServer in the first place. If your app is misbehaving, your app should hang, not the OS window compositor!

FWIU there's really no backpressure mechanism for apps delegating compositing (via CoreAnimation / CALayers) to WindowServer which is the real problem IMO.