Being that there were 31 games which could be qualified as "Good" quality (higher than 75% on metacritic) and 78 games that could be qualified as "playable" quality (60% or higher on metacritic) in Q4 of 2009 for the Wii, I think it is fair to expect a similar performance from the Wii in Q4 2010. At the same time, I think it would be remarkable if the Playstation Move could get 6 games of "Good" quality and 12 games of "Playable" quality in Q4 of 2010 because it is a new device, it is an add-on, and it does not seem like a major priority for Sony. This makes me think that the Wii will remain the best option for someone looking for this kind of gameplay experience; and aside from PS3 owners who also want motion controls the Move won't find much of a userbase, which means that it can't be much of a threat to the Wii.
With that said, if Sony can build credibility, develop some quality brands, and gain significant experience from the Move it could aid them in countering Nintendo in the next generation.
