I changed only a pair of PI, to suit the more hard working team. For one of the PF you can assign man marking the opposite deep lying playmaker or defensive midfielder (i mean, the guy who is responsible for starting the opposition attack deep on the field). For both BPD i removed "dribble more" instructions.
Wingbacks were more problematic. In a sub-top team, they are responsible for most of the assists, especially when your'able to buy players who both cross well and dribble, for example Balde in my Chelsea save. You can check also the latest review of attacante tactic from post no. 274, where the wingbacks role is so clearly emphasized. When you play as underdog, your team probably lacks of offensive wingbacks, and you're losing one of the ways of creating a real threat to your rivals if you're forced to removing their offensive PI, like "dribble more", "cross more" etc.
Last days i compared the new 352 mezzallas setup with the "old" 3412 with volantes. The old tactic in a cautious mentality provides more defensive stability, despite much less defensive-minded wingbacks, thanks to two volante roles, closing the space behind AMC back. The new version is really nice to watch, but for me it seems more unstable in defense, leaving too much space between mezzallas and your last defensive line. I was thinking about adding traditional DMC behind mezzallas and removing one the strikers, but it only made it worse. When you stop threatening your opponent it pushes you deeper and deeper.
Setting up lines of defensive and engagement lines can be also a bit counter-intuitive for many players. With many tactics, defence is the more effective, the higher we play, and the higher we press. In my Chelsea and Sociedad saves i had the best defense in the league but this is mainly due to the fact that we destroy our opponents' attacks in their starting phase, before they reach our 3 CB line.
Under current ME, creating more defensive tactic is really difficult and it usually comes to striking a balance between our satisfaction from the game, overall display on the pitch and the effectiveness of the tactic. Like
@vujevic said, all of highly rated tactics from fmarena are based on outscoring the opponent side.