In general, one instance of something doesn't prove anything. It shows that Roger's style can beat Buchecha's style, which is not the same as saying that it's as effective (and not the same as saying that it's less effective either).
At the end of the day, people have different ideas of what old school BJJ consists of. The fact of the matter is that BJJ, since its inception as a relatively young martial art, is a hybrid grappling style. If anything has defined BJJ over the years, it is constant evolution. The BJJ that the US was first exposed to in 1993 was already different from what Carlos Gracie learned from Maeda, because Rolls started cross training with wrestlers and sambists in the 70's. Was Royce Gracie's style not old school traditional BJJ? Then by 2000, watch the Mundials and see how the competition game had evolved in just 7 years. Compare that to 2010, when Roger last won the worlds. The game was even more different. And 7 years later it is even more different. Which category is old school? Which one does Roger fit into?