I understand what you mean by hyperbole. I think it depends on what you want from someone that cost £97.5m and £350k+ a week. In my opinion, when you get to that sort of figure you should be getting a player who is both able to impact the biggest games and drag the his team past any difficulties i.e. going down to ten men and/or when the team are having an off day.
In my experience of watching Lukaku he does neither and I cannot really remember many times he has done it in his career (I do remember a cup game against Chelsea for Everton and SAF's final game for WBA, but whilst those where good games, they weren't exactly six pointers/where silverware is on the line for his team.)
For me however all the evidence points to him being both a flat track bully and technically limited footballer. This at least is what I have seen throughout his career and I haven't been provided with any real evidence to counter it.
Now don't get me wrong there is value in having a flat track bully as he is handy in making sure those annoying 0-0's/1-1's against the likes of Burnley when they pitch in do not happen as frequently; I mean this season he probably got you 2pts against Zenit as that game would've probably been a draw; although equally is it any different to what the kind of thing Giroud is capable off the bench?
This said, when I watch Chelsea this year, I actually think their attacking play is worse than last season. I say this as whilst he is a better finisher than the others', his technical deficiencies mean that you're front line not as fluid as last season and not creating as many chances (although I do appreciate that Mount is very important to Chelsea as he is very good at harassing the opposition and dropping between the lines to offer the CM's an out ball to the forward line; so some of the issues going forward may be partly due to him being injured/looking fairly fatigued.)
Thus, for me at least, it is not so much that I think he is god awful, it is more that he really isn't a player that should be commanding such fees or even be playing for the likes of Chelsea and Utd as there CF1. Rather he is the type of player that is just a cut below and should really either be there CF2 and/or playing for the likes of Everton or in a league that isn't as demanding.