I would like to see some sort of auto updating support for 0 A D and you might be able to make use of Sparkle for mac http://sparkle.andymatuschak.org/ and WinSparkle for windows http://winsparkle.org/
There is actually some discussion going on in the Staff forums which might mean that we will move to Git sometime not too far into the future. I would say the question of an autoupdater and moving to Git are two different things though, at least in the sense of one program/tool/part of the engine that keeps the entire game updated. For everyone who uses SVN/Git already there's not much use for that + of course to have something that works on all OSs etc will take a lot of work. It is possibly so