Villa's struggled against teams who haven't given him space, as well. It's a tactical issue that is due to the lack of a distinct core - one that is partially (but not even close to fully) solved by playing Mix from the back.
If you totally discount the role that fullbacks play in the offense (some here do, and wrongly, IMO), the core of the team is critical. From the CBs to the CDM to the CAM to the strikers.
Villa, when healthy, has one of the striker spots on lockdown. I'm fine with Shelton at the other spot, and Nemec can do in a pinch. I actually like Mullins more than some others do.
But as you move a bit further back, I like Grabavoy, but he has no business playing attacking midfielder. Absolutely none. Granted, we weren't going to get a natural #10 in our expansion season, unless we signed a guy like Kaka on a DP. But we don't even have anyone who can play there capably, and it absolutely shows with our hesitancy and inability to play an effective final, killer ball.
Before you can worry about a final ball, you need to capably push possession up the field. Playing Mix as a deep lying playmaker works, even if it's not totally ideal - I'd rather him play in more of a box to box role with a Beckerman type of CDM. One who can serve as a halfback when we need to protect a lead, but makes smart, simple passes on a regular basis and is responsible defensively. Jacobsen is a destroyer, but doesn't give us nearly enough in direct play.
Frankly, even if the Centerbacks are okay defensively (which I argue - we've been very, very fortunate on some near goals thus far that could have made score lines look uglier), they aren't effective in cycling possession.
