I would have love, love, LOVED to see Tcl in that space.
100% agree, a Tcl based build system would be a dream come true. I wonder why they thought it would not enjoy widespread adoption. Plenty of Tcl-based systems did, after all, and it's only because of fashion now that people aren't still using it.
There is smake[0], which I use a lot, and lots of room to grow with (I.e.: dig in and figure out idioms), but Tcl/cmake could have been very interesting.
