As long as people get a choice to later install their favourite provider of maps or search, I am fine with anything that comes by default. Each company will "buy" their way to the default of something, be that a toolbar installed on a computer along with a program, a home page, etc.
Bing is freaking terrible, there are plenty of times when I search on bing, come up with nothing, go to google and get my answer within the first couple links. Bing is just Microsoft's way of expanding into the internet.
Uh, they did this a while ago (like a year ago) via a live update on my Tour, although verizon maps was the default map app. Of course, all I had to do was change the default search and it wasn't exactly hard to download/install google maps off of google's site. You're not locked into any app store with BB.