Just checked the official Street Fighter 4 site. I was right there are only 16 characters on that site.
The original 12 from Hyper fighting and 4 new characters
Abel- MMA fighter
El fuerte- Mexican wrestler
Crimson Viper- Cybernetic secret agent
Rufus- Overweight, American kung fu master (who hates Ken)
Anyway as I said before... dissapointing