It depends how Aguero scored the header goals. I have already explained that Lukaku scored those headers and other goals from crossings by just standing in the box and out-muscle defenders, so that means his strength and winning headers have been his main assets for him.
The hoofed ball isn't the main issue, we don't play hoofed ball at half way in all our games so far against top 10 sides this season, you are judging our playing style based on one game only against Spurs. We have played football with our feet in a lot of games and Lukaku has failed to score in those games. Positioning & his movement have been the issue for him, he doesn't give option for our midfielders or attacking midfielders to give him service. Even when we give him through ball, his run timing always late. No intelligence at all, all he expects is waiting & receiving the ball straight to him instead of trying to make a lot of good run and find his space.
You look at an example of our former goal poacher who isn't technically top class like Chicharito, the guy knows and loves to make run, find space and give option for our players to give him service. Sir Alex mentioned in his book that in 12/13 he wants his midfielder always go for early pass to split the defense by getting the best out of RVP's mobility and killer instinct. Spurs first goal basically sums up the mobility of Kane, straight kick off, Kane made the run, early pass from Vertonghen and basically split our defense. You look at Lukaku, he's not mobile enough, as a result our players can't give him early passes and defenders found it easy to mark Lukaku.
And players who aren't mobile like Zlatan last season & Berbatov at least technically top class. While Lukaku are both not technically top class & not mobile. Which makes things difficult for him. He has too many limitation to be striker in top club.