mature; it's easy". I, for one, am unhappy that Slime has so many features which I don't use/like/understand. If maintaining a fork were easy, I'd remove fuzzy-completion, presentations, and every line
it must be a social issue, because all i can do is wonder how can people use slime without the fuzzy completion... :) it's hard to estimate, but i think at least every 20th keypress of mine is the tab key while coding. but then i guess i should also talk about the length of names we are using... :)
and i must note that branching with darcs is only easy as long as there are few conflicts. no text based tool can handle multiple edits of the same point in a file. if we had a structured editor with a version control system that is preserving identities... but that's a different story and starts with "if".
maybe chopping slime.el into more files would help a bit? emacs sources tend to follow a one file per module approach, but having slime.el, slime-fuzzy.el, etc could work (unless i'm missing something).