But, one could argue, the "is it a function? or is it a macro?" confusion is a significant cognitive load on the Lisp programmer. These are really two different things, even though you can fit them into the same namespace.
Hoon has the different problem that you allude to - it is hard to extend the macro set at the user level. While this is fairly limiting, many FP languages, like Haskell, seem to do just fine without macro extensions. Perhaps typedness plays a role.
The bottom line on this problem is that there does remain a fair chunk of unused ASCII digraph space, so there is probably a way to put that in the programmer's power, but user-level macros are an unsolved problem in this relatively young language, nor is it one that obviously needs to be solved. But it would be nice if it does get solved.
You might get more cores at the same speed, but even that seems to be limited due to heat issues.
You can get more efficient CPU (e.g. SIMD instructions) but the compiler cannot optimize for them very well. Some people say implicit SIMD is a bad idea anyways.