1) removal of global $action
2) removal of Xml::hidden()
3) broken Output::add() (had to migrate to resource loader)
4) various parser tag bugs
5) removal of MessageCache::addMessage()
6) removal of ts_makeSortable() (javascript)
7) brokage of WikiEditor adaptation
8) MediaWiki:common.js no more loading by default (security)
9) addHandler() javascript broken in IE8
Most of these were deprecations, am I correct?