Great season? That depends on your expectations. When we signed Lukaku for 75M, all of us were saying that "ok, he will bring us tons of goals - but will not contribute lots in our open play a la Firmino". That was OK though, as long as he scores 25+ league goals he will win us a lot of points on his own. As it turns out, he hasn't delivered in front of goal. He has 15 goals, he has half the goals of Salah - ten less than Kane with more games. Less than Vardy, less than Sterling, a lot less than Aguero (who's been injured again).... Furthermore, he scores against the weaker teams. Headers and tap-ins. That's a great skill to have of course, can't deny that - but all in all not satisfactory for me. Also, he has only scored more than one league goal in one game, against West Ham on the opening day. A great goalscorer always scores more than one goal in several games - it shows their constant hunger. Kane has 2+ in eight league games, Aguero four, Salah six and so forth. Don't have to check Lewandowski, Messi, Ronaldo and Icardi, it's a given. Why doesn't Lukaku do it? Many factors here, but I don't think he's as hungry as the others. In his last 23 league games, Lukaku has only eight goals. This is all the games after his wicked start to the season, then it was like one goal in nine games - catastrophic stats and it cost us.
I am not saying Lukaku has had a bad season, but I cannot say it has been great. To be great, the guy needs to score more goals in the league and be ruthless, and he needs to score or dominate more against the top teams. As expected by many of us, he has not delivered against the best teams. He has scored once against a very poor Chelsea-side, that's it basically. As far as ratings go, I am stuck between a six and a seven out of 10. His output is just OK in the league, but there is still time to reach 20 (which is the very minimum expected from a striker such as him, playing nearly every game) - and I think he can finish the season well against poor opposition. The "lack" of goals as well as that long stretch without any goals puts him in the average-zone for me, certainly not great.