Weight is important for a handheld device. 1mm thicker would add a significant chunk of weight.
The issue wasn't as much capacity, as it was peak power draw. While somewhat related to capacity, 10-20% larger battery would not have made much of a difference. They could have crippled the performance and lowering the peak power draw, but that was what they did when it was necessary.
The issue wasn't as much capacity, as it was peak power draw. While somewhat related to capacity, 10-20% larger battery would not have made much of a difference. They could have crippled the performance and lowering the peak power draw, but that was what they did when it was necessary.