'anime' tag: "Most likely referring to Japanese style of animation and English term for animated series originating in Japan."
'animation' tag: "Movies or shows that consist entirely of either hand drawn or computer drawn/generated content"
I see anime as being a subset of animation and anime can be drawn in a wide variety of ways, some of which are very similar to non-Japanese styles. There are also many non-Japanese(more common in other Asian countries) animated works that are similar in style to Japanese 'anime'.
They are (as of writing) our 27th and 28th most active tags. I just don't think there's enough difference between the 2 to justify an extra tag, and I propose making 'anime' a synonym for 'animation', with 'animation' being the master.