Keep in mind that just because VA is in a BurPer blend, you won't necessarily pick up on a lot of VAs. Most of these blends will be that spicy/nutty that you're looking for...the VA in these cases don't necessarily add a ton of their own nature to the blend, they just sort of give the Burley a platform to stand on (oddly, the reverse is often true - using a bit of burley often helps push the VAs forward).
I'm sure actual blenders will come along to tell you just how wrong I am, but in my mind it's a bit like salting food as you cook - used sparingly it's not so much about making the food taste saltier, it's about making it taste more like itself, helping to bring the flavors of all of the other ingredients.