Again, this is a point of disagreement - I think hoofball, is still football. Route 1. Sometimes pretty , many times ugly. But it's needed to change things up. A player like Cristiano makes it look better when Chiellini lumps it up to him and he volleys it in past De Gea. If that's not an apt comparison then I'd say it's the same as a defender going up into attack, purely to provide that physical, plan b presence.
In any case, the other part of this is the pittance of a transfer fee. Anything substantial and its a missed opportunity. But at 7mil, my attitude is meh.
Going back to the first thing you've said here, I'm actually feeling the same about using Lukaku last night. It seemed like he was thrown in central to just compete with Burnley's physical side. Aside from not even coming close to doing so, it just seemed strange to move away from the kind of focal point Rashford has been providing. Definitely overthought by the manager, and or too gracious after the FA Cup display. Moving forward, I'm tempted to put Lukaku into the same category you have for Fellaini - doesn't mesh with the football style.