I haven't read all 38 pages, and I'm sorry for that, but I fear that if I read them all, I'll forget what I want to say by then.
For myself, I actually find the ASCII graphics far MORE pleasing. I really dislike most of the graphic sets. (Mayday's is good, but he has that weird O in his, so I refuse to use it.) I grew up on ASCII games, though, (and still play a lot of rogue-likes) so maybe that's part of it.
Personally, my biggest issue with getting started was how dense the UI is. More specifically, things like... "Why can't + and - work on all screens? or PgUp and PgDwn, or Spacebar/F9." It took me two tries to even figure out how to scroll most menus.
Next is that a lot of the things are hard to read, and/or naturally intuit, at least for me. Why do I need an Ashery? How do I make clear glass? How on earth do I make a well? (Not to mention that, esp. on the glass menu, a lot of the words are cut off, unless you tab the menu wider, something I always used to forget you could do.)
(At the time, I didn't have an internet connection, so the wiki was out.)
Thirdly, for me, is the lack of any real... characteristics to the dwarfs. I know they all have personality screens, and you can listen to their thoughts. But with 100, or even 20 or so, that gets unwieldy. I tend to play the game much more like an RTS than a lot of people seem to, simply because I just started to view it as "4 miners, 2 stonecutters, a glassblower and 7 hammerers. Send hammerers to attack, retreat my cutters, send miners to build X, Require more Vespene Gas".
*Having some in game representation of various things about dwarves, even just one sentence when you page over them "Aleph Mineypants, likes fish." Then next time it'll pull something else from their bio, so "Aleph Mineypants, worships Armok", etc.* (This would be BIG, at least for me.)
And most of all... 90% of the cool stuff you hear about is really rare and/or really hard. I rarely get to do any megaprojects. I've never seen nor heard about a mega-beast. And so forth. In my mind, that was the biggest turn-off at the beginning. I was hearing stories about carp attacks, and huge goblin sieges, and building giant glass pyramids. Meanwhile, I'm trying to figure out how to build a well, spending 2 hours of reading to figure out how to grow more plump helmets, and getting killed by a single raid of three kobolds.
And lastly... Dwarves are too stupid. This is the one that still majorly turns me off. I tell them to go inside... 10 dwarves go running around the countryside, until a goblin siege shoots them down mid-frolic.
That being said, I love the game. It's deep, and appeals to most of the things I've always wanted to find in a game. I find adventure mode really boring compared to most rogue-likes, but Fortress mode is like Crack Concentrate for me, so whatever.