I don't see the problem with the input part of the interface[1]. Unlike a lot of people, I know, and so I count myself as being the odd one.
However, unless you <tab> it away, you get a list of 'master keys' (that you quickly learn), and if you want to (d)esignate something you then get a list of what it is that you can designate to be done, and if you want to (b)uild something, then you get a list of items (or further groupings of items) that you can build... So if I want to build a construction, namely a wall, then... Well, it seems to work Ok for me... Maybe if I typo I'm going to go into the (b)uild a (w)orkshop menu, but that's a problem with any interface, whether it be keyboard driven or mouse-driven (and I believe that mouse-jitter from a bad optical-mouse-to-surface reading is probably a more common thing than having one's keyboard shuffle around uncontrollably while trying to type).
The biggest problem I have is having set up a complicated/convoluted Burrow and then accidentally deleting it when I had not intended the first character of the (d)esignate (d)ig two-stroke command to occur while I was still in the burrow-management screen. Perhaps a little "are you sure?" prior to such potentially effort-nullifying consequences? Well, that's the only suggestion for improvement that I have, and even then I know it's not really going to be a panacea.
No, back to the original premise, it is all organised neatly and (with some possibly arguable-either-way exceptions) logically. The biggest problem for a new player is not even knowing what they can do. Witness the occasional (but all-too-frequent) question of "how do I change levels?" Answer: ">" and "<" (among others, like zooming to a creature of interest). And anyone with a nethack background will of course realise this, but that culture is a bit less prevalent than it might have been a decade ago. But there's help-screens aplenty from the "?" key. And though
some won't even realise this, I can't think of many ways to make it simpler. It basically puts everything you need on the screen. Again, the difficulty lies in not knowing that (frexample) you can assign/change the nickname by going into a dwarf's screen (surprise, surprise), changing to the "
z:St" screen (perhaps a bit more obscure... 'St'=='Statistics'?) and then typing the clearly-indicated 'y' for Customise (again, maybe mildly obscure, but worth looking at, when first exploring the game) in order to then press the
very clearly indicated "n" for the "Customise Nickname" option.
Minor letter changes aside (or better names for the occasional section, but I deliberately chose one of the more obscure ones, there), I reiterate that I see no problem. I also reiterate that I know I'm probably not representative, but I'd still consider my POV worth emphasising.
Of all the things I found difficult, when getting into the game, it is not the UI, but the complexity of options that the UI has to end up granting. These not being problems, but features! When Toady introduced NewMilitaryInterface in .31, the problems were less (in my mind) to do with the interface and more to do with the whole difference from the original "place a point to which this squad will station themselves", what with the "target an individual" and various other options.
And I hold no brook with the idea that it is supportive of elitism, because
everyone does something wrong (whoops, accidental cave-in; whoops, siege at just the wrong time; whoops, migrants not having an entryway; whoops, I
really didn't mean to breach that...), but at the same time most of these issues only come to play once the first few hurdles (e.g. succesfully feeding and watering a burgeoning population) have been overcome. And, regardless, all these problems are a matter of management, not interface. The interface may indeed facilitate (or, by some people's measure, get in the way of) the management but it's not even as if it's a real-time control[2] that you need to prod away at in a timely fashion... The game pauses! Wrong sub-menu of the (b)uilding top-level? Come back out and go back in again. Not sure if it's a mechanism or a workshop? Explore. You will learn. We don't expect you to know from scratch, but you can get good at making a good guess even for the more rarely used sub-options...
Way too many words, sorry. Possibly some being apparently self-contradictory, if you read them in a way I didn't intend, but they were all consistent when they started to leave my brain, so I shall blame my fingers for any such errors.
[1] Nor the output one, but I
absolutely realise that my understanding of the ANSI-like/Page-whatever-it-is default tileset images has been honed through practice, and it's not everyone's cup of tea.
[2] Except for the military (s)quad-control one, which
is real-time, while navigating it, but still lets you pause it if you want to take your time.