Please don’t take this this the wrong way, but it is usually best to use a language for a while before suggesting fundamental changes. Also, its better to accept that fact that — for better or worse — a lot of the basic design principles of Julia are fixed now for practical purposes. The things you are talking about has been there from the very beginning (2012) and are the result of very careful consideration. See
Dynamic dispatch (if that’s what you are referring to) is actually crucial for some programs (eg those reading in data which cannot be typed a priori), and the performance impact can then be mitigated:
https://docs.julialang.org/en/v1/manual/performance-tips/#kernel-functions-1
You can search the forum for many discussions along these lines; they do come up from time to time.