Someone has to stretch the play high/wide if we have no wingers... It has been abundantly clear than none of Sig, Holtby or Dempsey are suited to playing out wide, although Sig has shown a bit of promise.
More penetrating runs from the CMs/incoming 'wide' midfielders would make better use of this movement, as would more creativity from deep, unfortunately our stagnant midfield coupled with Ade's poor conversion rate has meant we've been impotent in front of goal.
This is why Bale is a threat in the middle, we have no-one else as willing or capable to hunt goals as him. In his absence we need the entirety of our midfield to chip in goals through central runs and resultant poaching/shots from the edge of the area. Sigurdsson has scored a couple of back-post tap-ins after the keeper has spilled the ball, and nearly got one against Basel, and Dempsey is always a pest and a goal threat as he showed in that game. Holtby has yet to prove himself in this regard though, and Dembele seems genuinely scared of shooting, although is dangerous when he picks his moment. Parker still hasn't got a goal for us, yet he has had a comparatively decent scoring record at his other clubs.
I think Adebayor going wide is a deliberate tactical move as it both suits his game and that of our current 'wide' midfielders. Obviously he gets less chances to score as a result, and as a relatively poor finisher, can go several games without a goal. There should be more criticism of our midfielders for not stepping up to the plate and attacking the space he vacates..