I think we'd see much better performances from Schneiderlin playing at the base of a midfield three, like Baningime has in his last two appearances. Our spacing is good in that sort of system and Schneiderlin, despite generally being safe with his passing, is very accurate when he has actual options.
The line-up I'd most like to see at some point in the near future (not necessarily mid-week if we're prioritizing Watford):
We'll have some difficulty scoring from open play (a problem not unique to that configuration) but we'll be sturdy defensively and we should be able to control the ball some, with Rooney moving side-to-side and creating overloads on the flanks (think second half against Chelsea, before the subs). Sigurdsson offers a threat from set plays, and he and Davies can join attacks (not that Sigurdsson + Davies +Mirallas/Vlasic is who you want to be aiming at after some good build-up play but it's better than nothing). Plus, we have the option to drop a midfielder and bring on Calvert-Lewin or Niasse for the last 30 minutes to chase any goals we need.
We're a slow team as currently constructed so we have no real choice but to play deliberately. For whatever it's worth, I think if we had started in a 4-3-3 against Leicester, we might have actually been able to keep them out. The bulk of their chances came from Gray drifting into the space behind Davies/Gana.