I'm not referring to what he does now, as a center, on a scoring line. I'm planning for what he should be coached to do, and that he clearly has the ability to do, once he is assigned to the role that we are hypothetically talking about.
At the moment I would just be happy with a clean exit from the defensive zone, scoring in transition is secondary. Offensively that line should have pretty excellent possession and cycling, and Ennis can periodically try something fancy. If it fails, it won't matter as much because his responsible teammates can cover for it, and probably weren't going to get a great scoring chance anyways.
In the alternative (superior offensive linemates) Ennis' line would probably suck defensively, and more important players would be exposed to wasted shifts on account of Ennis' turnovers and lost puck battles. This is why I don't think he will stick with those sort of players.