Not in terms of new features.
XP is now on the "bugs and security issues only" part of the cycle, I think. You can of course pay money and buy support and enhancements from Microsoft for XP. But they are vey expensive.
Let's look at some others in the market:
Try waiting for any add-ons or patches for Fifa 00,01,02, 03, 04, 05, 06, 07 or 08. You'll wait a long time.
Trainz of course make you buy a new version of their simulator each year if you want enhancements.
Oblivion and Morrowind had bug-fix patches and you had to pay a lot of money for any of the expansion packs.
Train simulator had a small patch which fixed a few bugs and gave you a couple of minor extras. Everything else had/has to be paid for.
Anyone see the trend?