Aero is still kind of present in w8, just not called aero and you cant turn it off at all. However on w8+ internal stuff is way more optimized and thus monitor capture for example is unlike w7 actually really good and performs well.
There are no problems with obs and w8 and overall most of the "issues" people report about windows 8 are the users fault.
I dont quite understand what you mean about issues with aero though, except monitor capture every other source either doesnt care or works better with aero and if you really NEED monitor capture there is always the "new" dwm gamecapture which is basically monitor capture but requires aero on (which you want anyway). I guess if you hope to use something like the hd pvr2 and capture the softwares window and THATS why you need aero OFF, then you are out of luck because it wont work on windows 8 AT ALL due to the inability to turn aero off.
