I'd say there were two main phenomena that probably everybody realized about the break:
1) No balls going in, so this is a disadvantage for the breaker, unless a VERY powerful break is used with some luck,
2) the nineball got ALWAYS kicked by the 2ball towards the kitchen corner, or the middle, or with enough strength one cushion towards the foot corner.
Regarding point 1), Johnny Archer was smart enough to give the first break for Feijen, who then however completely outplayed Archer in every aspect of the game. Feijen also had probably the strongest (most powerful) break in the cup, and was able to make some balls out of the break, and, in fact, broke and run the table twice (which was a LOT with the break rule).
Regarding point 2), all the players acknowledged this, and there were quite a few nines done on the snap.
Something that some of you Americans might not know, is that on Eurotour, and in most of the serious tournaments in Europe, the break in 9ball has been negotiated quite a lot recently, namely on Eurotour we now have the 3-balls-in-the-kitchen rule, AND nine on the spot. In 10ball, there are break boxes in use opposite to that in the Mosconi cup (to avoid the middle pocket soft break in 10ball.)
So being comfortable with nonstandard breaks might have been an advantage for Europe. However, of course, I think only Boyes from the European team actually plays the Eurotour these days, or participates in tournaments in Europe. But maybe the captain Ruijsink had some tips to give them... he should be aware of what happens in European pool.
Edit. Oh I forgot to give my own opinion on the break rule... I think it was great, but I would like to add that the nineball should be spotted when made on the break. Well anyway, no matter what the rules are, someone is going to find a way to make balls on the break, and that's fine, it's 9ball anyway.
Oh and one more thing, personally I hate the 3 balls behind the headstring (kitchen) rule, there is too much luck and bad luck going on with that one.