Lukaku is boss and scores a lot of goals, especially when Deulofeu is allowed out for good behaviour, but for every goal he scores, his first touch prevents several chances for someone else in the team to score.
I rate him, but whilst I doubt we would get such a scary out and out striker, I suspect our goal output could be just as high if we had a player that was better at feeding those around him.
I hope he stays, but if he doesn't I think we can replace him with a player capable of helping to spread the goals around the team, and we could spend more money on players around that striker (+ a backup striker) that would be likely to bang them in.
Wingers are generally cheaper than strikers.
But as I say I really hope he stays, and tbh I hope we play two up front.