First thing that comes to mind is scrollback. I haven't seen one I liked in a console yet. With tf in particular, the curor jumps back and forth from the
input window (3 lines at bottom) to the output window. Its minor, but a little annoying, and quite possibly could cause death

.
I don't mind doing some manual configuration, but consoles tend to be a bit cumbersome in that area. I like to be able to easily select a font and size,
colors etc. Scripts for triggers, highlights and whatever I don't mind being more manual.
Another tf example, is keybindings/mappings or whatever. Other clients I have seen seperate the keypad from other keys. Keypad PgUp is different
than the PgUp key elsewhere. Similar to Keypad arrow keys and the solo 4 arrow keys on many keyboards. I haven't dug deep enough to find out if tf
can recognize these keys independantly of each other.
Speed seems to be another issue. With tf, I've made a big step in that area by changing my TERM variable (thanks jspectre), but it still isn't quite right.
I can live with it if I'm able to resolve the other issues. Most probably have a solution. I think the jumping cursor problem is more of a "feature" than
something changealbe though.
MUDix didn't seem to have any speed issues, but I wasn't running it in a terminal window. I don't think MUDix is configurable enough though.
In the end, much of it is ease of use with the exception of a couple of issues. I think that covers it. (not to mention the font issues I'm having with
linux in general. even after following many in depth instructions in another thread)