Best softwares for heavy pan/zoom editing?
Go with After Effects, it's a tool that will most likely stick around. If necessary you can also take advantage of the more advanced tracking an compositing features. 
If you end up editing in Premiere (which pretty much is the best option if you don't want to dive into Avid) the integration between AE and Pr is crazy useful. I find myself even making titles there because it's just a faster and lets me do prettier stuff.
Let me know if you have any questions.