Just one word: Bugs. You can only hope that upcoming updates will fix them.
Not the answer you're looking for:
Running Windows 7 in bootcamp on your Mac will give a better, more responsive AE, by a good margin.
DO NOT use Windows 10. Or 8.
Use Windows 7.
Otherwise, as Mylenium says, wait for Adobe to fix bugs. Sometime in 2020 things are expected to be performant and somewhat bug free.
Sometime in 2020 things are expected to be performant and somewhat bug free.
That's pretty optimistic for you, sir/ma'am; hat's less than five years away!
Seriously though, there's an update scheduled to come out at the end of this month that fixes a lot of bugs. Hopefully it fixes yours. In the meantime, try using CC 2014 - it may perform better for you.
Instructions on installing old versions: http://blogs.adobe.com/adobecare/2015/06/16/how-to-find-and-install-previous-version-of-ad obe-apps-in-cc-2015/