Oh... oh dear. Three pages of implications. Hmmm, as much as I like the idea of having all characters together in the same tag, you're right about that, on solo images it wouldn't hurt, but on those pictures with a lot of characters it could become a mess. I was thinking it could be helpful for quickly finding a specific character without having to check the wiki every time, as the tag suggestions aren't always available. For instance, searching for date_masamune shows me absolutely nothing but chickens, nouhime on the other hand, has a couple of suggestions at the very least.

(eta) ...I keep forgetting we can use the wildcard for image search as well. Can we alias wildcard searches? (Is this even possible?)