A much better idea would be to come up with a battery compartment shaped in such a manner that the direction the batteries go is self evident. This means the user does not have to make any additional decisions. This is a technology hammer applied to a problem that requires a different type of fix. The user now has to make an additional mental leap. It is not simplifying the world for people, despite what it does at first glance. It's making it at worst harder at best no harder than it is now.

All compartments (I could find around me) have the spring which holds the battery on the flat side of the battery... thats the indicator I use, without searching and reading any tiny diagrams

See, there you go. This was never a problem. Microsoft is trading the time you spend rotating the battery with your hand for time in which you have to read the damn instructions on the device.

I would never have thought of it because I've seen many, many different styles of endcaps at the positive ends of 'AA' batteries alone.

The way this would have to work, given the use of 'no additional components', would be by tying the center contacts together at both ends of each cell, and doing the same with the outer contacts. So if a cell's positive endcap isn't perfectly flat, it would be likely to make contact with both terminals at that end, which would short out the whole cell.

IMO, Microsoft's patent attorneys are only the first of many attorneys you'll be paying if you implement this scheme in a mass-marketable consumer device.