While being alienated by it at first, I tend to agree with your initial solution of [tag:blade-ii], since it captures the original title as accurately as possible (as also proposed in [this related discussion](https://movies.meta.stackexchange.com/q/1016/49)). While one could see it as *"just a sequel number"*, it is still part of the original title, in the same way as *Star Trek 2* isn't tagged [tag:star-trek-2] or [tag:star-trek-2-wrath-of-khan], but just [tag:star-trek-wrath-of-khan] and *Mighty Ducks 3* is tagged [tag:d3-the-mighty-ducks] (disclaimer: I've done that), even if *"looking awful"* (which, I agree, is not a particularly sufficient reason).