Maybe try moving Reus and Blas wider?
Failing that, if you're conceding lots of goals, maybe move Bender back into a DM position, and have Mykhitaryan operate as an advanced playmaker from alongside Gundogan (also with Reus and Blas playing wider). I find this is quite an effective tactic, especially against good sides. Maybe you could play more aggressively in home games and other matches which you expect to win.
Best way to find out what works is just to play the game loads and loads I guess. Like real life, one particular system won't necessarily work well for every side, and will be much more successful for some than others.