That sounds exciting A fresh take newly structured from the ground up. Can't encourage you enough if that tickles your fancy. This despite my dinosaurian micromanager tendencies.
It is very reassuring to hear that the old version will maintain compatability with DF for the ongoing future, though.
[As an aside, if memory serves correctly, there was an even older utility Dwarf Engineer (I think) which led to Dwarf Foreman. Interestingly, given the recent 'read only' versions of DT, it predated labour management and was a display only skill levels spreadsheet sort of thing. Someone with better search-fu than myself might be able to find some remnant of it in a dusty old archive somewhere...]
List dwarf skills?
Ooh nice, that one's even older..
The one I was thinking of listed the skills in a nice, if simple, graphic form rather than just being a csv output. Somewhat like Dwarf Foreman but without the ability to change labours. May well have even been the direct link between the two.
(DwarfSkills can still be found as part of this collection:
https://dffd.bay12games.com/file.php?id=1098.)
[Also I'll admit to some confusion on my part - Dwarf Engineer is/was one of the former maintainers of DT. But I've still got an image in my head of an earlier forerunner, I can see it if not name it...]
History aside, the point is that the features of Therapist have arisen because of the needs for them in the player-base combined with the the desire of developers/maintainers to add them. Doesn't mean that they are all still wanted/needed but chances are that someone sometime is going to want them again, or at least something similar that fulfills the same need.
For some reason Toady is entirely resistant to allowing players to access information in a conveniently usable form. Sure I can manually go through dwarf details screen after dwarf details screen to find out who is the strongest dwarf(s) in my fortress but honestly doing that 200+ times is stupidly boring. So there will always be a need for something like Therapist to list that information at a single glance. The situation is the same, if more complex, when managing work/labour assignments.