It was argued on a question once that syntax and word-order are not the same thing, yet I see these tags used both in the same questions.
What do the community think about this?
Syntax includes word order as a subset. There are some aspects of syntax that are not merely about word order per se. Ellipsis, government, binding, etc. aren't (merely) about ordering of lexemes but nevertheless are parts of syntax. We can have discussions that were in-scope about syntax at a level of abstraction that does not refer directly to word order. But word order is always about syntax.
I don't know what the SE policy is concerning tags that are supersets of other tags.
I'm afraid the two terms, plus morphology, are very often confused and, as a result, mixed. In the perfect world, syntax and morphology would be two separate branches, and word order would be one of the questions syntax deals with – the main one, I should think. In the real world, however, morphology and word order are, I would say, fine, but syntax can be used for anything ranging from 'word order' to 'word order + syntax + morphology'.
Personally, I don't support this merging in the slightiest, so my suggestion would be to manually correct uses of syntax where 'morphology' was meant, and maybe it would be also a good idea to incorporate word order into syntax?
