It doesn't bother me that much because it never misses what I type. I can hit the Super key, then 't', then enter, and I know that it will eventually launch a terminal.
Actually, you can't really trust that behavior if you ever install new software, or even change the way you use the computer by say starting to use some other program that starts with a "t" very often. The Dash optimizes for programs that you run frequently and some other program might win out if you run it more often than "terminal". The Dash is based on giving feedback to the user; that's why it needs to be fast.
CTRL+ALT+T might be faster in your case.
True, but you get the idea... I don't have to wait for it to "launch" before I start typing, so I don't feel like it's breaking my train of thought. This is mostly true with typing an address in Firefox too, because the history pane seems to ignore me at first which is much more annoying.