[elb2020]

If std::vector, std::array or std::unique_ptr could somehow have been implemented better without the use of templates in the C++ standard library, I think you'll find that they would have been implemented that way.

I don't know what you mean by "essential semantics", but the fact remains, as ncmncm says, that templates is the feature that allows new types of type safe generic abstractions to be built and added to the arsenal of C++ programmers. It's the feature that, most of all, has kept the C++ language alive and thriving over the past 20 years, in my opinion. Without it, the language would probably be dead.