When wenger came the game was changing. Scouting networks and diet/fitness were developing and his methods were cutting edge.
He was criticised for filling the squad with 'foreign' players and that was said by some to be 'wrong' and 'bad for the game'. We didn't care, we were winning titles!
When mourinho came along the game changed again. This time tactics were the key.
Top managers kept dossiers on opponents and adapted their tactics according to their opponent. Managers that did their homework knew that if they let us have the ball on the half way line and got men behind the ball we'd have loads of possession but go nowhere with it.
They also knew that we'd become frustrated and eventually there'd be chances for them. Our lack of height and physicality also meant we could be bullied from set pieces.
Rather than moving with the times, Wenger descibed such tactics as 'anti-football'. I would argue that our lack of reaerch into opponents' tactics and lack of changing ours is at best laziness and at worst neglect. With the right tactics we could have had a couple of titles in the last few years imo.