Granted, this is a beta, but I don't see Apple addressing all of the major issues in the next 3 or so months. Sure, they can fix a lot, but I think the OP has some valid concerns.
Also:
- Keep in mind that Apple could block a Google maps app, under the usual reason that it's too similar to an Apple app. There's no guarantee that Apple will allow a Google maps app.
- Even if Apple allows the app, Google probably has to write a new maps app from scratch, as the existing app source code is probably owned by Apple (I'd love to be wrong, though). Writing a new, high-quality maps app from scratch is probably not something that's easily done in several months. Because of this, my guess is that an initial Google Maps app, if allowed, might be missing a lot of features/functionality, just like Apple's map app.
- Given how other google apps like gmail and google voice are rather minimally-featured, it wouldn't surprise me if a Google maps app wasn't all that good.
On the other hand, Google would score a ton of brownie points by coming out with a high-quality maps app, and so there's a lot of incentive there. But, that gives Apple all the more reason to ban it.