It is VERY easy to fix this if you have a Dremel tool or similar device around the house.
The housing for nearly every headphone PLUG has lots of extra plastic on it. I have some Bose QC3 headphones that I love. I was not about to buy an awkward extension to put on the end of the right angle QC3 plug. I simply put a sanding disk on the dremel and removed a VERY small amount of plastic material and it works perfectly in the iPhone now. I took my time (about 1 minute) and my girlfriend could not tell it did not come that way from the factory.
I then proceeded to 'fix' a pair of Shure headphones that I use once in a while, as well as a plug in my car. All total, it took me less than 10 minutes to modify all three plugs from 3 different manufacturers, no detriment to the plugs robustness either.