When AVB was relieved of his Chelsea duties by Roman Abramovich, I felt he hadn't been given enough time.
As for his latest departure - I have a hard time using the 'he needed more time' excuse.
He had some time but there was something else he had that could have moved the club further forward.
Both Manchester clubs and Chelsea are in transition periods. This season was the perfect opportunity to close the gap at the top (See: Arsenal).
I don't know where he'll end up. However, I bet he is gutted that the Barcelona job passed by in the summer considering he had the deal in his contract that allowed him to go there if they came a-calling.