Turning into a caricature? I'd say he's already been there for about 10 years or so now. Sometimes I wonder if a script starts out with a completely normal character and it quickly gets morphed into that same androgynous freak that he plays every single time.
edit: Oh, and for those who saw MIB3, how is the K screen time split up between Jones and Brolin, 50/50, 40/60... ?