As someone who daily drives fish on ~4 different operating systems and loves it, I've been really excited about this rewrite and blown away by how fast it's been progressing given the size and complexity of the codebase. It will also somewhat lower the barrier to contributing for a lot of people, including myself.

Another thing I'm very excited about, which has received less attention, is the planned future fish rewrite to use UTF-8 instead of wchar_t (typically UTF-16). UCS2 and UTF-16 have been a plague on software and fortunately Rust makes working with UTF-8 a breeze.