The CPU decides how to attack based on probabilities, looking at what the best option is play-by-play. If going forward was a less viable option, the CPU would take its time a lot more. And so would players online.
Yes - this is absolutely true. I made a couple of videos about this for FIFA 11 and 12, in which I'm defending and the highest difficulty CPU is attacking, showing how if you deny the forward pass by blocking the passing lanes then the AI will go sideways and backwards.
YouTube - FIFA11 - Denying Progress.flv
YouTube - FIFA12 Demo - Tactical Defending
This is extremely difficult to sustain because of the aforementioned passiveness of defenders not under your control, like you said.
The thing is, if they fixed this one thing, I believe it would have three very important knock-on effects.
1) encouraging the patience on the ball that you mentioned.
2) Team pressing would become viable.
3) Thirdly and most crucially, formations would mean more.
IMO the main reason why formations don't feel like they matter enough is because whatever shape you choose, your defensive teammates don't get tight to their nearest opponent. So you could match up man for man, or have a numerical advantage or disadvantage in that area of the pitch, and they will
still be stood open regardless. So it makes little to no difference.
If two central midfielders cancelled out two opposing central midfielders, then putting a third in would make a difference. Right now nobody cancels out anybody, so why bother. The ball will be moved forward with relative ease anyway.
And this deficiency harks back to the whole 'ping-pong passing' hoo-ha of a couple/three years ago. They made some changes to the passing, making first-time, awkwardly angled consecutive passes less consistent, but failed to properly identify/address the major issue that the next pass was always available in the first place.
If I could change one thing about FIFA and one thing only, it would be this very subject. Fortunately I can mitigate it a little bit with slider changes, but that doesn't help the online folks and doesn't correct it entirely.