I would have liked to see more Vala and Carter interchanges. At first Carter was quite irritated by her and though she kept it professional she was obviously not connecting to her at all. Then suddenly they are going on shopping trips. Wouldn't have minded a few scenes between them to show how that happened.
I think Vala freshened the whole place up. Mitchell was pleasant enough but not really different enough to do that.. we needed someone quite outside the air force mindset. And Teal'c seemed to say less in the last couple seasons than in the whole series.