The lack of 32 gb is going to be a bigger issue than people think. I have a 32GB external for all my media, yet I've already run out of internal space due to apps. I don't consider myself an unusually heavy user. I have a few games and quite a few apps. My space requirements have grown dramatically because app sizes have grown dramatically over the last few years. A droid x with an internal 8 GB used to be enough. Now an S3 with 16 GB really isn't any more.
If I get an S4, I'll have to hold out for 32 GB models or pick another phone. I could probably get by with an S4, but resale value is important to me and in a year, the S4s 16 GB will a much bigger issue than it is now and it will be hard to sell.