The idea that a different screen size or a bunch of watch bands would cause a delay of 3 months is pretty ridiculous. The far more likely scenario is that either (a) there are serious hardware showstoppers, (b) yield issues with certain components or (c) the battery life is still unacceptable.

Also the single version of a watch is a really dumb premise. A watch is a fashion accessory so you need to support people's varying tastes.