This morning, Google had a Wallet developer Q&A session on the Google Developers blog, featuring Robin Dua, the product manager for Wallet.
Dua hinted that person to person payments could be headed to Wallet soon, so be on the lookout for that. He also emphasized Wallet's focus on getting small businesses on board with the company's loyalty reward and offer platforms.
More interestingly, when asked in a viewer question why Wallet was only supported on a limited number of carriers, Dua responded that Google was in active negotiations with "a number" of carriers, and that he "hope[d] to have some new partnerships to announce soon." While clearly implying that there is a possibility of failure, the fact that Dua spoke to such negotiations at all is encouraging.