I personally think that the shia-sunni tag should not exist on the main site, but since it seems to be used to ask the differences between Sunni and Shiism I think that is a fair reason to keep it. So I think it should be renamed or something, I saw we have on the main site a tag called differences and thought that we could clean up the "shia-sunni" tag and merge it with the "differences" tag and make it's purpose a bit more clear, but on review of this thought I found that the differences tag is not limited to simply asking the differences between sunni shia, but also between arabic words and different religions.
So what should we do with the shia-sunni tag? Of course it needs a bit of cleaning, but should we rename it? If so to what? Should we merge it with another tag? If so then with what tag?