Toady One,
I've enjoyed the heck out of your game for about four years now. While I haven't contributed nearly as much as your superlative work deserves, it amounts to more than my spending on any two other games in that time period.
But I haven't really had fun since 40d.
You just can't get to where you've been wanting to go for a long time now without fundamental changes to the way the game interacts with the player. A 25x80, extended ASCII interface and keyboard-driven menus haven't really cut the mustard since 2D days. Every Cool Thing you do makes the problem worse, and all your much-appreciated interface improvements - such as the one yesterday! - haven't matched the pace of your deepening and complexifying of the gameplay.
The other problem that's just killing me is processing inefficiency. Again, you've worked hard and effectively on this. Again, the improvements (and my much newer computer, built around a i750 chip) haven't matched the advances in gameplay. Every fort, every single fort I really care about and invest time and emotion in has died to lag. This has happened to me over and over and over again, and again the only solution for someone who plays the ways I do is to either stay with versions years out of date, or find another game.
This isn't good-bye. I'm sticking around. But until things change, and change fundamentally, Dwarf Fortress will never be one of my favorite games again.
-Fedor Andreev