I then installed GNL and after getting it set up, I forget about it and leave it alone. When I get bored again, I will just change Nova to be the default launcher and go through the whole obsession again.
Same here. I have Nova Prime sitting there, unused, since I got my Nexus 5. At first, I thought that GNL was sparse and the lack of options would get on my nerves. But as I got more time on it, the simplicity grew on me. I didn't need to have my launcher do a ton of things, nor did those things end up making my usage any easier.
Oh, JD.... I don't use hotword detection. Personally, voice control is a gimmick I typically just turn it off since I never use it. But the quick access to Google Now. Yes, I know you can launch it by swiping up (I do get to GN that way), but that will never match the speed and convenience of having it there on the left on the homescreen. It just works so much more fluid when it is integrated into the launcher. If Nova incorporated the same type of integration, then I'd consider switching.