If the API is fairly standard and the system specs don't contain something that will force devs to radically change their code just to get it to run - then the adoption rate from publishers should be decent. In that case it would come down to the commericals - what sort of incentives will Nintendo offer to get major support on board? (marketing support, access to Nintendo IP such as putting Link as an exclusive game character, a timed break on publishing royalties etc.)
niallyb