First off, I read your post. That's how I know I disagree with what you said.
Secondly, Martinez doesn't NEED to be a miracle worker. Lukaku's a striker who scores goals in the prem with regularity, he just needs polishing up on the areas of his game that don't come as naturally as goalscoring.
Thirdly, and with all due respect to Kevin Kilbane, I suspect Lukaku's a better player at 21 than Killa was at the same age.
You're saying no to a proven prem goalscorer on the grounds that there are things other than scoring that he hasn't perfected yet. At 21 years old. I think you're ignoring the fact that we don't have the money to buy a Suarez or an Aguero, and ignoring the fact that Lukaku may well be the best striker under the age of 23 on the planet.