If we rely too heavily on Rom then that's because he's our best player. He's world class, and teams in 7th usually don't have too many world class players. But almost every team above us relies on one key striker. When teams only play one striker formations then that's a given. Only Liverpool spread the goals around massively and that's because they don't have a reliable centre forward.
The only valid negative here is that our midfielders need to score more. And I think that's not a tactical problem or Lukaku's fault (5 assists say he actually helps others score) but just down to personnel. If we can sign some more quality players in the summer who can score goals from midfield then we'll be laughing. Mind you, we managed 3 goals today and only 1 of them was scored by Rom.