If we're looking at Wilson I think McCall must surely be planning to play wing backs this season. Wilson could probably do a job on either side of midfield, but let's be honest he's a full back and not the winger we're all hoping for by any stretch.
Given the squad this year I think it makes the most sense. I'd be a lot more comfortable with McManus playing in a back three for us, he was slow when he was at Celtic so god knows what like he is now. He could get exposed big style in a 4-4-2. In Hammell and ZFA we have two good options for a left wing back. I'm not sure how Kerr or Ramsden would cope on the right side in the more adventurous role of wing back, but if Wilson came in you'd assume he'd probably be first choice there, leaving Kerr and Ramsden to play centre back or cover for him.
It would also explain the decision to bring McManus in, having already signed Kerr back permanently, and perhaps why we haven't signed more wide players. Obviously if we go 3-5-2 or something similar, we'll be looking for good width to mainly be provided by the wing backs, and further on there would be less need to have an out and out winger. We could maybe use a back three (or five depending how you look at it) and have something like was suggested above with Faddy behind the two strikers. That should be plenty of ammo!