There are patches of Mozc engine for uim. but it is not merged to upstream. Could maintainer apply the patches and support "uim-mozc"?
packages on Debian have supported it.
# "Debian patch tracking system" is so useful. unfortunately it is not up to date version yet.
# a patch on Deabin is integrated one pacth file. it is easy to maintain it.
There is a problem using mozc_tool on uim-mozc. see following link.
*** Bug 421011 has been marked as a duplicate of this bug. ***