I havent unfortunatly. And this has been one of my huge concerns to the point ive almost took my wife's iphone back. The day i bought them the camera was fast. Soon as i synced the phones from a back up it takes 10+ seconds to even launch the camera (regardless if its from the home screen or the app switcher) and up to 15 seconds to save one photo!
So, this past weekend i deleted all the photos from my camera roll, saved them to my computer and re-synced them to my photo library. This did make a difference on my phone, but only slightly.
I think this is the WORST part of my phone. We just had a new baby 3 months ago and even though i make my money as a photographer we still snap tons of pics with our iphones. It drives me insane. I wish there was a way to fix this.