Ok thank you all guys, that helped.
After following all the discussion however, I still have a couple of question.
First: why is everybody mentioning 3-2 as an alternative to 2-3? I mean, why not man-to-man? Mod-CrazyEye gave a partial answer to that, but still, I believe that playing 3-2 versus look-inside or low-post you risk to allow a lot of offensive rebounds to your opponent.
Of course, it all depends on who you're playing against: maybe against a team with bad offensive flow and not so great rebounding it's more advisable to run a 3-2 zone, while as these skills get better man-to-man becomes a better option, what do you think?
Second: as far as I remember the latest GE update was early in previous season, so I'm wondering when exactly 3-2 started to be considered a bad option. I'm asking because last season I've played 2-3 several times with good results, and every time I've tricked my opponents into playing 3-2 versus my look inside offense (I like alternating the offensive tactic frequently in order to confuse the other teams) I've had very good scores. To me, the issues seem to have started with this season (or at least late in the previous one).