I think it would be great if we could add a series of buttons that would be for camera settings. I think it would really speed things up if we could toggle back and forth from perspective to parallel views instead of going through the command bar to get to everything.
Have you played with scenes at all? They can be very useful for setting and saving a standard visualization - They do save Parallel vs Perspective, too…
http://help.sketchup.com/en/article/39656
Toggling through scenes is quick and easy, too.
Another option you might want to look at is Eneroth’s Camera Memory tool:
https://extensions.sketchup.com/en/content/eneroth-camera-memory
Not to say it is not worth asking for commands like this in a future version (requests are great, keep them coming!), but these are a couple options for you that are available to you today.
Seems like this would be an easy fix if the ISO button could be used to toggle perspective on or off.
You can assign shortcuts for these commands and toggle faster than with any button…