Skin system rewrite currently supports old, SkinTemplate/QuickTemplate-based
skins. For example, Vector uses SkinTemplate and QuickTemplate and it works
well -- but as noted earlier, it won't support some of the new features
(SkinAfterSidebar hook and whatever else we may add in the future) until
it's rewritten. So no worries, you should have plenty of time to rewrite
your skins. :-)
Thanks and regards,
--
Jack Phoenix
MediaWiki developer