Is it possible that the 3.7V battery used in the 3DS would have evolved to better performance in 1 to 1.5 years? I don't know the first thing about the improvement of battery life efficiency over the years, but I was thinking that Nintendo could just start including a better battery in said time without doing a full redesign, kinda like the way they just slipped in the superior back-lit screens in the later models of the GBA SP. These better batteries would then be available for current 3DS owners to purchase and install themselves.
If it's not possible however, and these batteries will always offer the same performance for the current 3DS model, then we'll have to wait for a full-on redesign of the system before battery life would improve, or go with something like Nyko offers, which unfortunately adds weight and girth to the unit.
If anyone can elaborate on this that'd be great...
