Richard Stallman shares his views on why Tcl should be avoided, drawing on lessons learned from Emacs. He emphasizes that a language for extensions should be a robust programming language, not just an “extension language” like Tcl. Stallman points out Tcl’s limitations, including lack of arrays and linked list structures, and its inherent slowness. He also addresses the syntax, stating that while appealing to hackers for its simplicity, Tcl may seem strange to most users. Stallman notes that the GNU project will not use Tcl in their software, opting for two languages with different syntaxes to cater to different user preferences.
https://groups.google.com/g/comp.lang.tcl/c/7JXGt-Uxqag/m/3JBTj5I43yAJ