I don't see much changing with the iPhone 5 software wise, maybe a couple new features but nothing dramatic. They may alter the design a bit due to the antenna fiasco. It really needs at least a 4" screen. I think the Atrix will be the top dog Android wise if not over all AT&T phones but there is always something better around the corner
The only iPhone 5 rumors I've heard is that it may come with a dual core processor. Apple hasn't been know for keeping pace with Android phones in terms of specs so if they put a dual core processor in there I'd be shocked.
I doubt the iphone 5 will have 4G. It would add too much to device thickness, be too much of a drain to the battery, and LTE is too new. Dual core is more likely, but they may not utilize that, either.
It probably won't measure up to the Atrix hardware-wise.