I agree totally that the inverted winger formation is a big negative in our football at the moment.
When we had Sane and Sterling playing on their correct wings, we created lots of chance from wingers reaching the dead ball line and cutting the ball back. This is much harder to defend than wingers who cut back in to an already crowded park the bus defence. As noted above, Sterling has suffered most from this.
The other thing that has slowed our attack down is playing with two defensive midfielders, instead of one as we did previously. This has resulted in a much tighter defence, but reduces our attacking potential. Now that we have quality centre backs, perhaps it is time to play with only one defensive midfielder again.