These are very good points! I would generalize "functional" to declarative though: Logic programming languages like Prolog and Mercury are also much more amena

These are very good points! I would generalize "functional" to declarative though: Logic programming languages like Prolog and Mercury are also much more amenable to parallelization than C-like languages. In fact, different Prolog clauses could in principle be executed in parallel without changing the declarative meaning of the program, at least as long as you stay in the so-called pure subset of the language which imposes certain restrictions on the code.