Do we need composite tags, or will combinations of tags suffice?

Question

Looking again at this question, which I re-tagged earlier to use more generic tags as described here, I'm now trying to decide whether we need the [dx-vs-fx] tag. Whatever happens, I believe it should be replaced with a non-branded version, but if that discussion could be kept to the other question and this question be left to discuss the following:

Do we need "composite" tags, when both of the items that make up the tag are already included as other tags? I'm all for removing the [dx-vs-fx] tag all together, as anyone who wants to find questions comparing the two could search for both the [cropped-sensor] and [full-frame] tags, possibly with [nikon] if the brand mattered. In my mind there would be no need to have, for example, a [canon-flash] tag, as you'd just tag your question with [canon] and [flash].

Other examples I've seen are things like [canon-eos] on questions also tagged [canon] and [dslr]. I know you can get pre-eos cameras, but they're not the norm, and so perhaps I can see a justification for having a [canon-fd] tag, but [canon-eos] seems redundant.

Answer 1

In the interest of disclosure; I'd actually retagged that question to include [nikon] (at the expense of [format], which didn't seem as relevant).

I like the idea of some composite tags, after all there is a limit of five tags on questions. I think it's important to include the brand when the question is specific (Such as the one in question above) and there is potential to have a hierarchy that reflects the ranges within a brand (So maybe [canon-ixus] if someone wanted to know something specific to that particular range of compact cameras). After all, the interesting/ignored tags support wildcards, so [canon*] would highlight (or hide) the composites just as well.

Perhaps the best approach would be to be monitor which tags get used, and merge those that are too specific.