Right now, I think the main problem for Sony is to define the Arc (or Move). Gamers know the technology is way ahead of the Wiimote, but the aimed casual target just won't see the difference with the wiimote unless Sony is able to show or explain it simply and clearly.
I read some people saying "eventually, Wii owner will asked for something more...". Why would they ? HD graphics were and still are all over the place but ppl keep buying the Wii, showing years after years that visuals are not what's matter to them. Maybe that will change, but by the end of the year ? When Nintendo has a stronger line up than 2009 ?
I don't think Sony can just come and say "hey, it's like the Wii but with HD". It's not going to work. they need something else, and I'm not sure they have it.
Last year, when they presented it for the first time, it was like a science project, an interesting toy but w/o any vision to back it up. Compare to project Natal which already had a strong name, a very clear vision going beyond gaming and something to set it apart from tha Wii (no controler at all), it was really weak.
Beyond technology, beyond support, It's going to be a marketing call and Sony really need to find some trick, staring with a proper name, and they need it for the E3.