Technically average is not correct. All you have to do is just watch some of his goals on youtube. Is Harry Kane a technical striker?
Also he is not just a big lump, he's a strong striker with very good pace.
I understand you feel underwhelmed by Lukaku but come on, but Lukaku is not Duncan Ferguson, he is not Bas Dost, he is no Mitroglou, he is not a Slimani. He is a top striker with pace and skill who has time and time again proven himself to be great in the Premier League.
Don't get blinded by "popular belief".