2014-11-30, 08:24 PM
Because drastically changing things for 1.8 (a minor point release) would mean there would be no themes, or plugins, that would work correctly with the release. Obviously, that would put a lot of people off upgrading and would cause more problems. The decision was made early on in the development of 1.8 to not change things too drastically, but to give the system a bit of a facelift.