my one gripe after using mc for a few years is no parallel transfer support. it slows down significantly when transferring small files compared to one large file.

That I agree with. In Total Commander I typically do F5 copy and then put it in the background F2. Then start another.

This isn't possible in MC. And also a concrete parallelization is not available. This sounds like a feasible feature request to the upstream MC project! I'm sure Gnu Parallel or just pure C code would be able to handle parallelization of copy jobs.

EDIT: Wait! It does have background transfer now. Which means my technique of how I do it in Total Commander will work in MC now as well. It is almost like having Parallelization.