I strongly believe that TTY compatibility is a feature which should not be discarded. But that doesn't, I think, prevent the kind of features you mention: they just need to be first-class UI features like the minibar is.

Agreed that Elisp needs to be upgraded. I think that it should just be replaced with Common Lisp, which has namespaces (packages), and is very fast, and whose implementations support networking & threads just fine. Of note, part of why Emacs regexps are so unusual is that they are pragmatic: since they will be used to match Lisp source so often, () are not the metachars they are in other regexp dialects.