retexturing the lesser models would be a much faster way to go, and would make more look better much faster. It would be a good way to go until there are better models made, and it is likely the new textures could be easily tweaked to fit any new models made afterwords anyway, so it is a win win going for better textures first, at least in my opinion.
just look at the WMRP, the world map has fairly outdated modeling, just like much of the game, and just by making the wonderful new textures, it makes something better for people to use, and at a much faster pace than completely remodeling the map. a full remodel of the map will likely happen at some point in the future anyway (even though IIRC not much is known), so why not just hold people over with something much better than what is already in the game?
maybe at some point a group can get together to retexture the enemies and such, while a separate team (or the same team, just waiting until retexturing a lot) starts on remodeling, and after a model is done, they just make tweaks to the updated textures and be good to go. it would be faster, having more done and released much sooner than doing everything on one model at a time. by the time one decent larger enemy model is completed, a few enemies could have new textures done, to hold people over until the models are finished. sounds fairly good to me, but I am neither texturer or modeler, so I wouldn't know how it would work in reality.