Full Screen does behave weirdly in a number of ways. In a quick test with a Safari full screen window, activating another app brought it to the front and sent the Safari full screen off to another space.
I am a huge fan and power user of KM, but I also use a few other tools.
In this case, I use LaunchBar as my primary app launcher, and activator. In most cases I have a LB shortcut of 2 or 3 chars. So to launch/switch-to Keyboard Maestro, I just type "KM".
Just tested it with Outlook 365 in full screen and it worked fine.
Yep. I used SL for a long time before I got LB. LB offers the advantage of allowing the user to specify the shortcut abbreviation to use. It is also a great tool to open all of my key web sites, based on bookmarks I have saved. For example, to open the KM Forum in my default browser I just type "KMF" and then RETURN. If I want to open it in another Browser, I just press the TAB key to send it to another browser.