I think that they should stay but should be used relatively sparingly. We should come up with a good excerpt that limits what they do. For example, there are a lot of rather basic results that come up during introductory courses. Questions related to those kinds of things should get the tags. Things that can be approached from either direction should not get the tags, e.g. international trade should have its own tag.
The problem is that we could end up with every question being tagged at least one. That makes for a pretty useless tag. If we keep them, then we need to find definitions that limit their scope.