Hello Nyalathoteps_Cousin!
I don't think you are bad about liking the UI as it is, although I would not talk about "dumbing it down", as this does sound a bit elitist (^_^;;.
Anyhow, personally, I like the interface as it is. I am horrible at using the mouse, so if I had to designate things using the mouse, I would have to do (or rather re-do) every designation about five times. Add to this that I like to make all surface ponds initially marked as restricted traffic zones, being very precise about that, and also mark surface streets using traffic designations to encourage trampling saplings in the streets while not harming those in the free areas, there are a lot of designations that require good precision.
I guess, besides habit, which also adds to it, it is also a matter of what playstyle you have. I haven't turned invasions on in years of playing the game, concentrating on building things and managing trade and production in fortresses with minimal migration (pop cap set to 7), so there is not the need for me to manage tons of goblinite or hordes of dwarves. I prefer to play in a slow, relaxed manner where I can put a little tweak here and there, a style that, in my opinion, works best with the precision the keyboard controls give me.
Thus, I am more than happy with the way things are currently.
Yours,
Deathworks