Being a long time DP user, I recently tried out Cubase 7 (the free trial). Spent a few days basically mirroring my template that I have in DP (700+ midi/audio tracks) and i'm not sure if it's the VST3 use of Cubase or that Cubase is just that much better, but the stability and performance I got was pretty amazing. I had the template FULLY loaded, and was able to keep a buffer of 256 and the CPU meter was barely sweating. I never thought my Mac Pro could accomplish such a feat.
In DP, I have a downsized template of about 300 midi and audio tracks. (using about 36 of the Event Inputs) and it can barely handle that at 1028 buffer.. the CPU freaks out about every few hours and I have to restart..
Not sure if a MAS version would help, or if DP could do VST3 (i know that's on their side) but it's a shame that seemingly these Event Inputs bring down DP like they do. Plus all the problems with Drop notes, hanging notes, etc. I am greatful for the Event Input work around though.. I know it's just a band-aid to the stupid AU limitation..