Hmm, as Jakg says, S3 will be another product with a few years worth of extra development. Unlike most publishers, we only charge the *difference* to our existing customers, not the full price again. So your S2 purchase is 100% saving against the S3 price, if and when there is an S3 in the distant future.
It's a bit like saying, I'm upset because I have to pay more money when I move from a 2 bedroom house that I've already paid for, to a new 3 bedroom house.
Anyway thanks for getting S2 and I hope you enjoy it. I expect there will be loads of free updates for you to enjoy in the next few years!