There are a lot of dialect questions that come up, most of them about Kansai and Osaka variety. It seems somewhat redundant that every question about any specific dialect will also have the "dialect" tag. Should these perhaps be merged, or become aliases?
If it's a good thing to minimize aliases, then I think they should be merged. There's only a handful of prominent dialects of Japanese while the other dialects are pretty obscure. I'm betting that almost all the dialect questions will be about kansaiben or ainu. Well, Ainu語 is not really a dialect. It's nearly mutually unintelligible and can be technically classified as a distinct language from 標準語.
Otherwise I think there should be a minimum of two tags, kansaiben and dialects, because a dialect tag is needed, and kansaiben is so prominent it might be more beneficial to users to grant it its own tag.