It'd really have to be a big update, otherwise they would have no real purpose at all. You wouldn't really be able to show them off or anything(except to IRL friends), because the Wii doesn't have a network. Xbox has Xbox LIVE and Playstation 3 has PSN. The Wii only has Wifi, and no real network to go along with their online stuff. You can't view a profile, send friend requests(aside from Friend Codes, which are also separate for every game) like the Wii can, Without a network, the awards would pretty much be for nothing, not even for show. If they made a big update like that, though, it would mess up a lot of things. Friend codes would be unneeded and all that, people couldn't have the same name, etc.
However, if they created a new console they could easily do it on that because they wouldn't be messing anything up at all, it would be starting fresh with a new concept.