I was quite sure we would see reports of Bluetooth issues after the ICS update. I had bluetooth function issues in both my aftermarket Sony car stereo and my Infiniti factory audio system, mainly involving bluetooth media audio. I also found that if you disable media audio in the pairing settings, it would ultimately lead to auto-repairing issues for the phone side. This was on every ICS leaked build I flashed, up to and including the final release version. I posted about it all over the place but a fix never came to light.
How did I fix the issue you might ask? I flashed Cyanogenmod 9. The Cyanogenmod team and the developers who ported it to our phone and created a kernel for it succeeded where Samsung failed ... regarding Bluetooth at the minimum. Samsung builds great hardware, but software is not their strong suit. Hopefully that will change some day.
The best I can suggest is to report your issues to Sprint. Once enough calls come in regrading Bluetooth issues it may get on a fix list and sent over to Samsung. Until then, you may just have to deal with it, or consider doing as I have. Flash an AOSP ROM like CM9 and never look back.