Just launched a small tool at github.com/SublimeGit/CanISwitchToSublimeText3
It does exactly what it says on the label: Tries to figure out if all the plugins you are using work in Sublime Text 3. Feedback is very welcome
Just updated this to use the new data from Package Control 2. It should give much better results now, so if you haven't tried yet (or even if you've tried before), now is the time to do it
Works great ! Thank you !