Try Professional. Some of the experiences I've had with them is more "believable" in terms of football, versus video game. Top Player and Superstar are not difficult, the over-aggressive defending is counter productive actually. \
On Professional:
Attack
- Forces passes, gets deflected
- Multiple deflections in a row
- Poor long balls and through balls
- Clearing the ball
- Passing the ball backwards, including to the GK
- Moving ball from side to side vs Forward-Forward
- Att Level reacts to the flow of the match, regardless of minute (usually on higher levels, the only increase/decrease in levels is 70+ minute)
Defense
- Maintaining shape
- More standing fouls
- Moving up in press relative to ball's position
Here, from 2:16:30, a very fun match vs Flamengo, as Corinthians.
http://youtu.be/IRRzdWoNnTU?t=2h16m38s
Throughout all my testing on Superstar and Top Player, Flamengo have started at "green" or level 3 defense. This is the first time that they actually have started on Level 4 defense.
This indicates to me that Professional is where they truly adapt to who they are playing. The CPU also plays much more controlled and make plenty of proper mistakes.
You can see they are actually "thinking" behind their build up, and not just blindly passing. I agree though, wish there was a bit more of a killer instinct.