I am just wondering, as it seems like the reliance on the network is a problem... if it could be localized and pull updates periodically while sending feedback to a central repository, I think it could be faster...
Not anytime soon. The amount of data and processing power Siri requires needs at least a whole roomful of servers, probably more like several roomfuls, and wouldn't even fit on an ordinary desktop, much less a mobile device like the iPhone.