In speaking on personal perspective, the term 'franken' used to mean (to me) 'a non genuine watch comprised of some or all genuine parts'; at minimum, a genuine dial was a requisite for me to consider a watch as a 'franken'.
Anymore... I don't really even bother with the idea of such labels. I think the hobby, in all it's many facets has different meanings and offerings to us all as individuals. Some of us build watches to look as close and exact to genuine as possible; I fall into this category as I find the process to be challenging with the end result very rewarding on a personal level. Some want to customize what they have to make their watches unique and oft times completely different than what the standard fare of any given watch may have started as. There are some out there that like to combine parts from several different manufacturers to make something truly unique and one off. In a way, perhaps all of these approaches could result in something termed as a frankenstein. And really, you have different degrees of each school of thought as well, from mild to extreme.
So, I think the interest, and perhaps end goal is just to have fun with it. Make it whatever you want it to be. There really aren't any defined rules regarding the matter, nor should there be