Both crews performed well on the course and both made mistakes in pre start (maybe Alinghi one more).

BMWO was most of the time the faster boat. What made the boat better?
BMWO has a longer true waterline: 130ft vs 101ft according to yachting world.
BMWO uses the full allowable width. (Why does Alinghi not?)

The wing. I think most will say that the wing was the key element. It is just so visible. But after the second race, I am not that sure anymore. The smaller platform could go more or less the same vmg upwind. Of course with stronger winds the picture would be different, but Alinghi showed a huge improvement and one might think where they would be, if they would have more boat to boat tuning, maybe even reviewed sail cuts. I account much of the advantage downwind due to the faster trimming of the wing. BMWO was more stable (I rate the helmsmen as comparable). On the reach leg, the longer and wider boat will always be faster, go on a reach with a T and you know what I mean.
There are also some other aspects in the rig: Uni vs sloop (on Friday), genaker with or without overlap, etc.

Curved vs. straight boards: Alinghis straight boards are canted. I guess there is little difference. ALinghi has both types, and we can assume that they selected the right one.

So in my conclusion the big difference came from the larger platform (on the reach BMWO was 5kts faster), the faster trimming downwind and the better prepared boat/team of BMWO.
Alinghi probably hadn't have the time to design and build a wing. But they must asked themselves why they selected a shorter and slimmer platform.
Behind each technology, there are men, which need to have the right understanding and ideas to make it. Hence: 3) "better team effort and understanding of sailing" which in consequence lead to 1) "better boat".

Cheers,

Klaus