Are you sure u r comparing the right cameras?
The A55 is an advanced Entry level DSLR / DSLT, dont compare the A55 with Canon and Nikon pro level DSLRs like 1D mk 4 or D3s. Those are pro spec cameras, its not surprising that they have more AF points, and comes with a BIG price tag as well.
Lets compare A55 with advanced entry level DSLR of Canon and Nikon instead:
Nikon D5100: 11 AF points (1 cross type) with a burst mode of 4FPS
Canon 600D: 9 AF points (1 cross type) with a burst mode of 3.7 FPS
Sony A55: 15 AF points (3 cross type) with a burst mode of 10 FPS
So if 15 AF point (with 3 cross type even) is considered not enough for you, maybe u will like to point out to us, which entry level DSLR from Canon or Nikon has more AF points than the A55?