Really, I do a normal double click and it registers perfectly. I remember how it was on my previous phone, so all I could say there's no reason to fix hardware problems with software (and it would be unfair too: if Apple produces defective products, it's their responsibility to replace them with normal ones, and they do).Please explain why lengthening the delay between home button pushes would cause problems.
I'm not talking about changing it a lot but just enough so the software knows when you MEANT to do 2 clicks or only one. Right now, the home button seems to malfunction during 1 click and the OS sees to impossibly fast clicks (way faster than any human can physically click the button twice in a row). If they slowed the duration between the 2 clicks just by a fraction, they could avoid having the OS respond to the 2 rapid (impossibly fast robot clicks) that look like only 1 click to the user.
By the way, (regarding your earlier comment) not every single proximity sensor has been fixed with 4.1 (this forum is full of the proofs), so it just explicitly demonstrates that you can't fix something that is totally flawed.