While in theory your idea is right, there's a very apparent problem with it.. Technically, the people who didn't buy the DLC shouldn't have access to these models. They have, but the units simply aren't unlocked in their game. If modders unlock these units and retexture them, they still have access (in some way or another) to these units, which isn't the way it should be..
There's another debate going on about this as well by the way:
http://www.twcenter.net/forums/showthread.php?t=271950
Personally, I think the idea is great. You won't believe how many historical source images from the early 18th century I've seen where the infantry looks more like the pikemen in-game than the regular line infantry. The Blue Guard model (as it stands right now) could indeed function as some sort of an early line infantry and artillery model.
But yeah, there's the whole debate about what we can and what we can't use in our mods. It would definitely be helpful if CA provided some perspective on this. For instance, it is definitely illegal to make the DLC units themselves available through a mod, so that people who don't have the DLC can still play with those units. However, to what extent would taking the unit model (which everyone has, although some have it unlocked and others don't), retexturing it and giving it another purpose be illegal?
It's a riddle, wrapped in an enigma, placed on a slippery slope in treacherous territory..
