What should we do?
- Keep: [tag:nxt] and [tag:rcx]; Unusable/'Reserved': [tag:mindstorms] OR - Keep: [tag:mindstorms]; Tag synonyms: [tag:nxt] and [tag:rcx]
However, there might be questions which aren't so much about a specific Mindstorms kit but rather about robotic design in a more general sense. If these questions happen, taging them with rcx or nxt will be ill-suited, while mindstorms might be better — although there maybe robotics would be best (let's not forget Spybotics :-).
My own suggestion is to keep all three tags for the moment, but specify in the mindstorms wiki that if the question is specific to the NXT or RCX, then the appropriate tags should be used.
But really, I think we don't have a sufficient vision of what questions will arise to make that kind of decision now. Then again, I'm tagnostic, so my advise isn't worth squat here.