One feature I really wish iTerm2 2.0 would have introduced was better session restoration support. With Terminal.app, you can issue a command like 'ls' and then quit and re-open Terminal.app and the previous output from 'ls' shows up. This is incredibly useful when you have to restart or if your system crashes and you have some output that you wanted to preserve. I see from the changelog that some type of restoration…
Nope, no restoration support yet. I'm concerned about the performance hit.
Would that mitigate your performance concerns, or did I not guess the source of the issue correctly?