Woah if they did reject the app, they'll be screwing us customers. They should approve it so customers have a choice to choose what works for them. Since Tim Cook already suggested the Google Maps web app as an alternative, I think there shldn't be any hiccups.
Apple have proven they are quite at ease screwing their customers over maps so it really wouldn't surprise me to see Google maps rejected.
For the last few years my reasons for jailbreaking have gradually diminished, Apple maps actually added a reason though, I'm sure there will be some tweak to change the default maps, just like there's tweaks to change the default browser.