Not sure what you're on about, central midfielders are generally not known for being big lads. What we need from him is a better engine than Shipley and Westbrooke and the ability to put the odd tackle in
Bakayoko isn't bone idle, I don't think that's fair. He is just inconsistent, he can get himself across defenders to get on the end of crosses (see the goal at Charlton and home to Walsall) but just doesn't do it often enough, he's too static.