Things that we would like darcs 3 to do differently from current darcs ("getting it right the first time around").

But on the other hand, beware THE SECOND-SYSTEM EFFECT...

• UTF-8 metadata
• Unicode filenames? http://bugs.darcs.net/issue1863
• conflict marking
• robustness wrt unsupported filenames (internal representation of file id?)
• patch format and bundle format
• support for merging unrelated repositories?
• better preferences system (maybe be done earlier)
• symlink support? http://bugs.darcs.net/issue820
• using a .darcsrepo directory instead of _darcs http://bugs.darcs.net/issue129
• sha1 hashing everywhere (patches, repos, repos state)
• handling of various patch types: "usual" patches, bug patches (a la bugs everywhere), etc. ( http://bugs.darcs.net/issue1786 )
• binary diffs http://bugs.darcs.net/issue1233

• a packed+hashed format for repositories (issue1535)

• improved handling of filenames: AddAddConflicts [HARD]

• patch format that properly supports the distinction between tag and non-tag patches
• fix commute with respect to null-hunks (Hunk line [] [])

• improve support for token-replace patches (doc refers to some limitations due to the current patch format), maybe it does not worth it ?