Away from home I think we need Barkley behind Lukaku. Barry and McCarthy get swamped in a two away from home and neither have the range of passing to get us from back to front quickly. We have to try and build the play up with a two man midfield -  something most sides on their own patch will not let you do. When Barkley drops in we are much more solid as a three to keep the ball rotating and to run the ball up the pitch on the counter. I don't mind Naismith out wide away from home a he effectively shuts down one flank and his pace energy and stamina are always useful away from home. McGeady is virtually useless at grounds like Turf Moor and Osman's lack of pace is a problem away from home.
At home, especially against lesser sides, I see no reason why we couldn't have Lukaku paired with Naismith or Etoo flanked by creative players like Mirallas and Pienaar/McGeady. In an ideal world I'd have Barkley probably alongside McCarthy in a midfield two but I can't envisage Martinez ever going for that (especially after the Barry Barkley disaster against Palace last season).
In short Lukaku is your main man. We then have a raft of options to play alongside or behind him who can all score and create goals. Naismith has had/will get his playing time. If that's starting like he did in the first few games, on the flank with Barkley in the team, or coming off the bench like he did last season, we know he's a quality player who will get us goals and gives us a different option to Barkley Lukaku Etoo and Mirallas (still can't believe they all play for Everton). That is what having a quality squad is about. We're just not used to it because its been a few decades since we had a decent attacking unit. Remember we've still got a 6 million pound striker to come into the squad as well.......