1. The PS2 lacks a bit of hardware shader support. The GC can do something like that. If the PS2 stacks up to the Cube, it matches with the XBox as well.
2. Why play DDR on a console? You can get a clone of it for free on PC. Stepmania is an opensource DDR clone.
3. Sony has placed a big PS2 trailer in front of the Braunschweig main station. Apparently the PS2 has like 90% racing games, a few jump&runs, a few RPGs and that annoying Eyetoy. Or at least that's what Sony considers worth playing. My friend went in there hoping for DDR, but there was none... (NOTE: GTA was missing. They are not allowed to display "mature" games in places where kids could see them, GTA is rated 18 here.)
4. More isn't better. If I just wanted MANY games, I'd have stayed with my PC. Absolutely every genre is present there.