If the intent is really to introduce a requirement, the verb "shall", instead of "must", shouldmust be used.

:-)

I agree that something should change here, but I don't think replacing 'must' with 'shall' is a complete solution. The next sentence says that the program is not ill-formed in the case where the template keyword is missing; instead, it is interpreted in a different way. It's possible that we could fix this by changing the 'must' to a 'shall' and deleting the following sentence.

We should come up with a specific proposed change here and check with CWG before applying it.

[temp.name] is just an example. I noted that it's wording will be changed if CWG issue 1710 is adopted. But there are several other places that uses "must" where the verb "shall" seems more appropriate. As another example, 18.6.1.2 [new.delete.array]p12 says

Requires: If present, the std::size_t size argument must equal the size argument passed to the allocation function that returned ptr.

I would prefer to address the "must"s on a more individual basis, to ease review. We probably don't want to address "must" in notes and example, for instance. Please create individual editorial issues, one for each section with a specific issue you want to have fixed.

As an example, #493 highlights a specific issue.