While I realize that Bucky has been Captain America for almost a year now I feel I need to contribute my two cents on the matter.
For me Bucky is the sidekick. He's THE sidekick but sidekick is the operative word. He's not as fast, strong or smart as Steve (Rogers). While I like the idea of Steve Rogers Agent of SHIELD - hell yeah - I just can't stomach Bucky as the leader of the Avengers, Steve as the leader of the Secret Avengers. I think it should be reversed:
Bucky leads the Secret Avengers (in keeping with his time as the Winter Soldier) and Rogers leads the regular avengers as he has done for decades.
What do YOU think???