Eh, it isn't that extreme, but fact is if you rushing 4 you probably going to leave 1 guy open given enough time. You either need to generate pressure or commit to cover 4 style defense in pass downs. Also investigate whether you need to be matching up on route running, could help.
Since getting more hardcore about managing defense Ive managed to hold the AI to about 65-70% completions (in yr 3, 79 overall def, 75 speed thresh, all else default).
I usually make sure I have a corner on both TE / RB unless it's 3rd and shorter, or if playing a zone. LB's on man are terrible (as they should be) and you can only get away with this if you're getting consistent pressure.
That being said... I think the tweak that needs to come on both user and cpu is a little more pressure. Way too much time to throw at the moment with standard 5 man line (almost never bother keeping a te/rb in to defend). That and toning down the run game and this is an absolute gem of a game.