Not only do modern compilers give better error messages (with room for improvement still), it is possible to make use of enable_if and if constexpr/static_assert to give proper error messages for templates, and when C++20 gets widespread enough, concepts.
Modern clang (usually, there are edge cases) gives pretty good error messages over all. And like you point out, if you use constexpr you get even better messages. Hell, I watched some cppcon videos over the weekend and learned that clang can even detect out of scope access of temporaries when in a constexpr (but not otherwise sadly), and also that in many cases, a lot more of a program can probably be constexpr than we might think.
The talks were by Jason Turner, who has an ARM emulator implemented entirely as constexprs and a test suite that runs at compile time (so if it compiled, the tests passed). Obviously for actually interacting with it, its not running at compile time, but the logic has the ability to run at compile time, which is pretty cool.
I personally call it "old school" vs "new school".
"Old school" is asically the programming languages that originated in the 70s-80-90s. An incorrect but an illustrative way to describe error messages for them is "The programmer needs to suffer". They are any combination of cryptic, terse, complex, exposing internal machinery of the compilers and linkers etc. There are many reasons for this: computers were not powerful enough to afford better code analysis, parsing, backtracking etc; the users of the tools also knew the tools and could tinker with them etc.
"New school" is from late 2000s on. I usually say it started with Elm. Clear messages pinpointing the exact problem, solutions to problems inside error messages, error clarity as one of the priorities in language/compiler/tool design.
