On my short list of stuff that I would like out of MU/Client tech?
The ability to support basic image formats (jpg, png, etc). This would be helpful for doing things like pulling your basic Infobox off of the wiki for a character. When I +info Mike, it pulls up his infobox from the wiki, with a nice PB at the top and his most important info at the bottom of that, so that I can see at a glance what I should be paying attention to.
Persistent text when I re-open the world. If my computer crashes, I don't want to go and have to look up in the log what I was doing, I want the client to just load that already up to a certain buffer size. That should beconfigurable for user preferences.
The ability to split screens and send stuff to a different screen in the same window, like what the Evennia webclient can do now. Should also be configurable re: size and position.
The ability for a character to be in multiple places at once. How many times have all of us here been in a situation where we are in a scene with one character, and then proxy that character with a different character in another window? This is common enough that this limitation is just flat-out dumb at this point.