I see your concerns, I have them, I can see the other side of the argument, at times he looks poor, disinterested, with the touch of a baby elephant chasing a peanut, people are concerned, I mean this is a player we are probably gonna have to break our transfer record for, your talking 20m+, so of course people have doubts.
But hes a 21 year old Striker, I recall watching his first few games for Chelsea, he was actual LOL bad, hes come on since then and I can imagine he will only get better, but IF, by some miracle hes reached his peak at 21, hes still an outstanding goal scorer, rather than a scorer of outstanding goals.
People have this "dream", a dream in which we pick up the next Michu for 2m, the next Jela for 5m, well look how that turned out in the end, hes scored over 30 goals in the last 2 seasons, I honestly cant be bothered to check actual facts, but im pretty sure if you added up the total goals scored by Everton Strikers in the last 5 years, its doubful you would get to 30, people also have this idea that theres better value around, Remy for 10m lads, despite him being a money grabbing weapon with questionable morals and also pretty nailed on for Arse, Bony, who with only 1 season in the bank, seems a gamble, mostly given the fact he would probably cost around the same fee.
So sure, I can see why people have concerns, but at the end of the day we need a top class striker and I consider Lukaku such a player.