The mechanical tag is pretty useless -- nearly the entire bike falls under this category, so using this tag doesn't really help anyone. There are a few electrical issues (which may go up as electronic drivetrains go up; unfortunately, proprietary-ness will often mean going to a shop for the servicing, and we don't really do electronics of lights and stuff) and aesthetic issues, but they're more the exception than the rule.
Do we need still it?