Well, I guess there's been improvements (file transfers appear in a window~ yes!), but... custom away messages aren't saved anymore (ie, upon quitting with an away message up, restarting adium won't cause you to start with that away. And pulling up the custom away message thing is a pain.)
Accounts, to sign on, and such, are now on the bottom of a very long menu (due to the number of saved aways I have).
Messages, while more... customizable, are now less so, because you need to learn how to edit the layout crap in order to change things. As in, you edit files now, instead of changing options. XP
Buddy list view options have increased massively - much more customizable, almost as good as the original Adium (1.6?). Props!~
It's much more... disgustingly userfriendly. Such as the ugly "Events" preferences "pane". It's a copy off of AIM's events sorta thing, and the general setup (lists? Must click on each to add an event, one by one... needs multiple-item select.
Accounts, are now shown as a list (like the events), and editing them triggers a new drawer-window from the windorbar. I liked the older version, mostly because there's less... fancy crap. fancy crap=more steps=slower.
 Oh, and the Growl update? It made the bubbles bigger (like, there's an extra line for some odd reason). ::annoyed::