I'd be really intrigued to see the statistical difference having McBurnie on the pitch makes, I bet it's pretty sizeable.
There's undeniably organisation issues defensively, with players regularly scoring unmarked. The more intelligent defensive teams know opponents blocking routines and don't let it happen, hence why we've been noticeably worse at it in the Premier League. I still don't think we have any absolute monsters physically. When you look at the likes of VVD or even someone like a Zouma, they'll just dominate everything to win it. None of our players are that strong. Certainly no one like JOC, Maguire or Morgan of old. I seem to remember Trusty having really impressive aerial dual stats, but he hasn't looked impressive it that regard... Or any other.
Ultimately we lack the personnel and tactical intelligence to defend at this level, especially given the sheet volume we have to deal with.