I can see why it is laid out the way they did.... the 'big black bar' on the right is the shutter button, they could have made that a little more clear with one of those first-time tool tips... and a TRUE view finder is awesome... drives me a little crazy that I see so many people complaining about it 'cropping' their photos. Again, they could have tool tipped that as well.
Now, they could have split the shutter button into two equal sized slabs on either side of the view, but that would have lead to its own set of issues. The most problematic one would be that their new design approach is that stuff slides out from the left of the screen.... settings, menus, etc. That slide out menu pretty much forces the shutter to the right hand side.
But I'll say it again... from what I can see, this app is going to develop into something quite good so be patient. OK, this version might seem like a step back, but it isn't really... From what I've seen, they appear to have ripped the guts out of the program and completely redid a lot of it. The pics I've taken, so far, have been as good, if not better, than the previous app. It seems to focus quicker, take quicker photos and not hunt about to keep focus as much. For what it does, I've found that it does it better than the other camera app.
I can only guess...but Google seems to have made the decision to release the improved camera app, with limited features, early rather than wait longer for a more feature-rich..... And since it's in Google Play, it is optional...