I'd like to see a consistent backstory for Hotch (and they'd better not forget that he has a brother, even if Sean is an annoying prat), a lot less of JJ and Garcia's hangers-on, an open investigation that runs, or has run, over a very long period of time...

More of Erin Strauss (~ducks and hides~).

Prentiss backstory.

Some of the team's teaching or research/publishing work.

And a throwaway reference to the guy 'down the hall' who takes on the really weird cases would make my year!