Given that I am not a vi user, ESC being there doesn't matter to me.
There are the F keys when debugging, but I tend to jump between them and mouse anyway.
Since I only use Mac devices occasionally at work, I guess all in all it doesn't make that bad impression on me, versus fighting single keys for input.
As a vim user, I always use Ctrl-[ anyway instead of escape. So I map my capslock to control.
(Although nowadays I mainly use a kinesis advantage keyboard so non of that matters much anymore. Hell, many of vi's features like hjkl movement don't matter anymore either as all the modifier keys are all easily reachable now)
There are the F keys when debugging, but I tend to jump between them and mouse anyway.
Since I only use Mac devices occasionally at work, I guess all in all it doesn't make that bad impression on me, versus fighting single keys for input.