Just because the options are between 32bit and 64bit does not mean that it's a 50/50 split.No, they won't get rid of 32 bit for a long time. They might start making 64 bit used automatically if your processor supports it, but there's no way they're going to get rid of a huge client base that still doesn't have 64 bit machines.
32bit has only token support in any OS, and is no longer the standard distribution. Every year people that were on 32bit, upgrade to someting with 64bit. It's going to happen, and Blizzard is prepping now.
HB's insistence on using 64bit is rediculous, as all it takes is to look at any and all clients running on 32bit to start narrowing down accounts.