Can't say I've been a big supporter of him, but I was just looking at the NL saves leaders, Cordero is tied for 9th, but is only 3 within 4th. Only 4 saves seperate the 4th and 11th leaders in saves in the NL.
He has 6 blown saves, which seems like a lot, but I started comparing him to the closers up there near him, and noticed he's not too far off:
8) Brandon Lyon, 5 BS
7) Trevor Hoffman, 3 BS (but 1-6 record? Go figure)
6) Kerry Wood, 5 BS
5) Billy Wagner, 7 BS
4) Kevin Gregg, 7 BS
3) Brad Lidge, PERFECT 31/31
2) Jose Valverde, 6 BS
1) Brian Wilson, 3 BS
Besides Lidge, Wilson, and Hoffman (maybe?) - I don't think Cordero is any worse overall than any other closer in the NL. Maybe he's overpaid, so he gets more heat, but his performance isn't bad compared to other closers.