The narrative that we weren't any good when he left caught on but I don't agree, we won the league in April and were robbed in the CL against Real. Ferguson gifted Moyes Zaha too, which people forget, who has proven to be a good player and much better than most of our other wide players in the years that followed. That was on Moyes that he fell out with him.
Five or six years later, Mourinho was often using a back 5 of Ferguson signed players (De Gea - Valencia Jones Smalling Young), which doesn't say much for the recruitment after him. There were other good young enough players at the time that seemed good at the time like Kagawa, Hernandez, Welbeck and others that were good players if they were developed further at the right time. Ferguson wanted to get rid of Rooney, again that would have been for the best in hindsight.