I like Irina too. It's such a complex character. And I wasn't dispaointed with the way it ended. Her obsession for Rambaldi was alwyas her priority, although she loved her daughter too much.
Season 2 was the best mostly because of Irina beeing there.
Yeah, Vaughn did change but he was always the same boyscout, rsking everything for Sydney. Losing Sydney helped him to see things on a different way... and Lauren's marriage made him darker and he stopped trusting people.
I miss these characters
Jack in my fav after Syd and Vaughn. What a grey character and his last scene made me cry.