The biggest deficiency in texmacs is not in the software - it is the lack of good free manuals. Many programs do not come with full manuals. Documentation is an essential part of any software package. When an important free software package does not come with a free manual, it is a major problems. We have many such gaps today.
It is unfortunate to see a Directeur de Recherche of CNRS and the main developer of the Gnu TeXmacs Software System, writes a guide on mastering the secrets and latest versions of Gnu TeXmacs. Even worse, the book is written in english, yet the terms of sale are given in french.
And with the hefty price of 50 Euros, who is he supposed to be kidding. Because many people are not laughing or pleased - to say the least.
Why is this? The authors of good manuals write them for publishers, which published them with restrictive terms - no copying, no modification, source files not available - which maken them non-free, thus excluded them from the Free World.
And given that writing good English is a rare skill among programmers, we can ill afford to lose manuals this way.