I was happy to see Kristin Wiig go. Although I think some of her characters were funny, the majority were just annoying.....and sometimes characters that started out funny became annoying. I like a number of the women on the show now much more than I ever liked her. For me, Amy Poehler was the biggest loss as far as female cast members to depart recently, followed by Maya Rudolph.
When they were talking last season about Wiig, Andy Samburg and Jason Sudekis leaving, I was only upset about JS leaving. I don't miss the other two at all. I'll be sad to see Sudekis go, whenever that happens, although I think Tara Killen could fit into that "everyman" spot quite nicely. He's really improved over his time on the show.
The problem with the last few seasons isn't the quality of the performers, it's their inability to write for themselves. You have to have both to succeed on this show.