I don't think he was ever tactically inept, was he heavily reliant on coaches? yes but he had the foresight to delegate to coaches whom he had a role in picking so for me that shows he was tactically quite advanced. I just think he was unable to appreciate the value of possession and that his tactical reading of the game, in terms of how to dominate a midfield against a big side which can keep the ball was slightly flawed.. but I think with age on his side, he would have cracked it.
For me where the problems began with Fergie was his age and growing sentimentality, he kept players and signed players who had no right to play for Manchester United.. and 2006 onwards, his signings became ever more questionable. His 'eye for a player' is what got worse and that is why we needed to move on from him, the ruthlessness wasn't quite there and when it did surface from time to time, that is when we saw some cracking decisions.. like isolating Rooney and that two-legged tie with Madrid which was Fergie at his best.
You look at the 94 United side and it would walk the league now, same could be said about the 99 side or the 08 side... these sides may have been 4-4-2 or whatever but they were athletic, technically gifted, full of flair... basically these sides possessed the hallmarks of championship winning sides and Fergie managed these teams brilliantly. It was just a shame that his standards began to drop with age.. guys like Scholes at 30+ would not have been kept on in the 90's era, he would have replaced them right away... guys like Valencia would never have got into the 90's sides.
That is why we have had to get rid of so many players, LVG hasn't put a foot wrong in terms of getting rid of the players he has.. in fact I would argue there are still quite a few first teasers who shouldn't even be here and that is the legacy of Fergies last few years. He took a very average group of players to the title and whilst it highlighted what a great manager he was in terms of getting the best out of a group of poor footballers .. at the same time it highlighted how much he had declined in certain facets of his managerial ability, i.e. his ruthlessness.. that squad was not a typical Fergie squad. He left us in a pretty poor position.