sure, but most of those are 'light' mods -- basically jsut taking the images from the other game and moving it over. Some companies "don't care" because it lets their fan base move their brand into new markets. (still falls under copyright issues, but they care less).
What was suggested was not 'just' the art, but the whole gameplay side. That's far beyond what a company would look past.
whether or not modders would 'care' doesn't actually matter.