The only problem is on the forums, not in real life.

Currently, the BTC unit is divisible to FAR below the point that anyone cares.  And if we start getting transactions down to that point, it is trivial to extend the protocol.  In fact, we will probably extend it for technical reasons a century or two before any real life transactions need the extra digits.  Yes, I said centuries, and no, I wasn't kidding.

Why not worry about something that might become a problem in your lifetime rather than making up this crap?