I would be GREAT to have Brenda Leigh Johnson of the D.A. Office come over and be involved from time to time with Major Crimes during its (hopefully very long) run. I'm not saying often, but say once (or twice) a season, on average, would be wonderful. After all it would allow us to see her keep her statement / promise at the end of "The Closer" to see everyone around the place.
I don't know if the actress would be into doing guest spots on Major Crimes, but IMHO it would be wonderful for the fans. Of course, till the series has made it on its own, I'd hold off, but ... then bring her back for say a two part episode where the D.A. Office and Major Crimes has to investigate together.