I just did some work on GDict today, mainly improving my reimplementation of the protocol implementation (since MIT's dictionary server appears to be gone, I threw out the old protocol implementation and rewrote it to use the one given at www.dict.org). My new implementation has some pretty nice features: non-blocking operation, automatic creation and destruction of parallel connections, and so forth. Getting the UI to the point where it really takes advantage of this protocol is an entirely different story. I am a tad concerned that, while MIT's protocol supported cross references (which basically make the dictionary act doubly as a thesaurus), RFC 2229 does not. It would not be difficult for a server to implement that functionality, by adding an additional strategy for the MATCH command, but that support would be nonstandard at best. Spell checking also presents a problem in that regard. Hopefully I'll get around to fixing up the UI code some time soon.
It's looking pretty good, though.