If you look at bjj 10 years ago, and compare it to the bjj of today, you will find two different sports pretty much.
The average level of athlete is MUCH higher nowadays, and the techniques are much more developed as well.
On top of that, most of the champions of today have far far better wrestling ability as well due to cross-training.
Some examples of "new" developments to bjj that differ from the classic system are:
the 50/50 guard
Eddie Bravo's "no gi" system (which a lot of people hate on)
There are many more things out there, and more to be discovered.
Personally, I think it is foolish to NOT study everything, because even if you don't use it... at least you can defend against it.
Now, a match Joao Assis and Jeff Monson