It is a replaceable part, assuming that Samsung makes it available (The part). To date, they have not. Some people have broken their already and tried to have the phone replaced and Samsung said no, as they consider it to be a cosmetic damage, like a scratch or crack.
I was worried about this same thing, so i bought one of those aftermarket QI wireless chargers and use that most of the time to charge. Takes longer, but the battery lasts a lot longer than my S3 so I only need to do a charge at night now, as opposed to late afternoon as was on the S3 so I can just let it sit there for 6 hours plus.
Originally Posted by meissen
I'd be tempted to remove the door entirely - it's a pain having to remember to remove the door every time I want to charge my phone, especially when docking it in my car.