Won't be a big deal. Maybe they'll go along with the 2,5mm jack plug. It's a lot smaller and thinner. Last time I saw this used was on the old Nokia 5510 phone.
I guess Bose will sell a lot of Bluetooth headsets if this happens. This is not a big deal since there are lots of quality bluetooth headsets on the market. Less openings for water and dust to enter the phone ;D
Bluetooth doesn't have any problems with bandwidth, audio quality and battery drain anymore.