Actually I think they're right about using the same little battery across all their models. Many have more than one Sony camera and with one interchangeable battery it makes life much easier. Also bear in mind that bigger battery means inevitably bigger and heavier camera. Unless you're a machine gunner, 300 shots before stopping to change a battery; what, 30 seconds? Can't be such a bind.Looks like Sony fixed ALL issues I found except for a short battery life.
With 35mm film it was every 36 shots, medium format, even more frequently. I do think popping a couple of small batteries in a pocket is well worth the difference.