VQ does the same thing as SA and BR. Players should choose what is best for them.
YOur right, it does DO the same thing, however the opportunity cost is no where near the same.
OC of BR is forgoing another passive, (and 15% of mana cost as life, which really isnt a cost as explained above).
OC of SA is the cost of another passive.
OC of VQ is the cost of another passive AND the cost of giving up 1 cast per 5 seconds to use a primary.
Just a quick example.
I have 1.16 APS. I can cast bears 5.8 times per 5 seconds.
Bears do 236% per bear and can pierce. Lets assume a SINGLE target, and only 1 bear hitting. I would do 236*5.8 per 5 seconds = 1368.8%
Now lets assume 1 of those 5 casts is a primary. Lets go with Widowmakers.
I would now do 120% +4.8*236%. Total of 1252%.
Thats a DPS loss of approximatly 8.5% by casting Spiders.
Now lets assume we are attacking a Elite pack. In this case its very common for your bears to hit multiple targets, and also every bear hit a mob. So lets assume each bear hits 2 targets.
3*2*236*5.8= 8212.8% damage in 5s
Now cast WM 1 time per 5s,
Net DPS loss of about 15.8%
While VQ definitely has its uses, it has a far higher OC to use.