I must say I personally feel that FM 2008 is by far the game in the series that I have had most success in by tweaking my tactics. After a bit of a slow start my 4-1-2-2-1 tactick has started to work wonders and I'm currently undefeated (1 draw, 8 wins) in the Adeccoligaen in Norway with ByÃ¥sen, playing with more or less the same players I failed to gain promotion with the first season in Norwegian Second Division + some players on loan from the Rosenborg U19 Team.
What I did was basicly decide what tacs I wanted to play based on the original staff of the club. Got in some good trainers. Got players that actually did do the job.
I got no funds at ByÃ¥sen. The board refused to let me pay anythhing more than Â£250 a week in salaries, and only Â£3k all together (350/4k now). Just about no players want to play for me. If I try to sign the same player as anyone else, either on loan or on free transfer I will not get him. I had to work for over a year to get all of my players into full time contracts. On top of all this, when my tactic started working after the first half season and I go on to win the Second Division in the second season, the board makes a Â£4 million stadium expansion basicly crippeling my financial gain of getting promoted for all the season making me unable to buy even those few willing to play for me (and in the process, telling me to sort out the financial problems...).
Now, I still haven't lost a game in the Adeccoliga. And belive you me; there is a huge jump player wise from Norwegian Second Division to Adeccoligaen.
So basicly. The game works quite fine in my humble opinion. Sure I have had a few matches when I had 100s of shots on goal and the keeper just won't let anyone past (to be honest, most of my shots doesn't hit the target - those who do often go in), but they aren't very common and they usually doesn't last if I make tactical changes in the half time and tell my boys to stop shooting like blind cows (half time talks).