TeXmacs is a true WYSIWYG scientific word processor. It's not a TeX/LaTeX GUI front-end. Rather, it has its own typesetter that produces quality comparable to TeX in real-time as you type.
TeX has a huge ecosystem built around it (Latex, Contex, many others). It's going to be very difficult replacing that.
Better build on what exists rather than replace it.
ftp://ftp.texmacs.org/pub/TeXmacs/macosx/qt/TeXmacs.dmg
TeXmacs is a true WYSIWYG scientific word processor. It's not a TeX/LaTeX GUI front-end. Rather, it has its own typesetter that produces quality comparable to TeX in real-time as you type.