The ExTeX project is building on the experience of the many existing TeX development and extension projects, to develop a new TeX-like system. The system is to be developed in Java (like the ill-fated NTS project).
While ExTeX will implement all of TeX’s primitives, some may be
marked as obsolete, and “modern” alternatives provided (an obvious
example is the primitive \input command, whose syntax inevitably
makes life difficult for users of modern operating system file
paths). Desirable extensions from e-TeX,
PDFTeX and Ω
have been identified.
Usability will be another focus of the work: debugging support and log filtering mechanisms will please those who have long struggled with TeX macros.
ExTeX will accept Unicode input, from the start. In the longer term, drawing primitives are to be considered.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=extex