Watching games doesn't make a big difference in Match results,

[Al Svanberg]

I am not agree with that, as I usually tend to see a good effect when I do substitutions, or move players of position inside lines like invert the MC's left-right and vice.
+attending is a +8% and this is something that after seasons one can see that can make a differance, in terms of chances.

Another thing is that, if one don't attend the scenario is one, and if one attend, the scenario is another.

Yeah I agree.

I think a good experiment would be to play like 5 friendlies vs the same opponent with easy tackling and then 5 friendlies vs the same opponent with hard tackles (make sure conditions are as similar as possible in all games, conditioning, morale etc). Good stats will be available and I am willing to bet that fouls, cards etc will be affected a lot by this. That is at least my experience, tough tackling and you seem to get a lot more fouls etc.

In general, I also believe that it is important to remember that any setting is just orders at to what preference players shall use. I mean, if you set go down both flanks and play like a DC-DC-DC-MC-MC-MC-AMC-ST-ST-ST you will not see many attacks down the flanks. Passing options down the flanks will not be available for the players. Like giving an order is not like an order in chess. There obviously is a great deal of randomness in this game which also is the case in the real game of soccer, who can for sure know how a real game will play out?