Sorry tl;dr but I can try and answer some of your questions. From what I know most of the custom models will remain. I believe the idea of the devs is to have all the import models (such as the Moldy Crow and the Talon) replaced by custom ones. I might however be wrong here. There are several custom models that I believe will be replaced with highter quallity ones. As for the variety I believe your choice is quite diverse as it is, adding more ships willl just make it more confusing.