I tried playing a 5-3-2 (131-111-11) vs two of the best teams in French league.
The whole idea was to park the bus in front of my goal and hit on the counter, and guess what…I got thumped 0-6 and 1-5.
What is worse is that the both games, on both sides, was focused on central play. Now my team is rather average but it’s still a good team with good overall players in all sectors of the field. What matters is that the sides are not that disleveled
Anyway, the logic of my approach is supposed to guarantee a strong defense and make the life hard for the opposition. I gave up part of my offense and midfield so that my zone would be covered. I could still very much lose the game, but not get humiliated like that.
Second, the very approach of the opposition with central play going head on against my “wall” is usually a futile approach. Looking at the replay, they had a field day like I had five sticks they could easily go around rather than 5 organic beings with limbs in full motion. And let’s not forget two midfielder tracking back too.
Breaking a “park the bus” defense would require a good use of wing play, which neither opposition did. I do realize I’m relying too much on RL observations but some logic has to follow even in this game, me thinks.
Of course I go back to my offensive style of play, that’s what I do better, but I still think nowdays football should be smth more than an Eredivise reflection ;-)

I havent seen a team succeeding with a unique formation, my experiments only cost me points, for example i stopped trying wingers last season after some disappointed results. I used both wing and mixed play style.

How about a feature that allows you to play your clone team? :P For example: Your 1st team against your 1st team. Then you can play around with tactics without worrying about loosing points or getting fired. And since the team quality would be exactly the same it would be obvious which tactic works better.

why u want to play against your own team? There is an option called friendly. If u arrange it good enough by msg a manager and agree on playing your main squad for like 2 matches u can try out things :P thats what i do normally in the beginning of the season ;)

That is the fun of the thing, if you make too much experiments you can suffer some bad results but you learn something… It is like that in real life, we just need to find a balance.
Regards
PS: I used wings in the CL last season and it worked fine, some other teams are having good results too.

Personally, I believe to have 1-2 formations with great balance when I used to have a strong team due to quality loans. Before the start of last season I sold me best players and pretty much bought a whole new team of young potentials aged 19-22. The approach has been great, so far my starting 10 outfielders average an improvement of 32 pts :). So the team is still improving and not yet able to compete for top placements. So, against teams I know I will have a hard time (expected to lose), I do experiment, because the result won’t matter much. This experiments are indeed for “emergency” tactics I will need in the future when my team has reached “full potential” (in parenthesis because there’s always space for improvement) and is fighting for titles :).
In the case above I am commenting the result of my last experiment, which i was a bit shocked, because even though I expected a loss, I also expected much more resistance from my tactic.

You can easily get relegated if you experiment too much in Brazil Seria A. Thats not a luxury you have.On the other hand its kinda boring playing with same way all the time, most teams playing with same kinda formations. Its a risk reward thing but personally i gave up. Good luck to you.

Try 9-0-1 or 6-3-1 with defending midfielders with center play and often long pass =)