Here is how you can fix the problem, and make a lot of money at the same time:
Add uzi drops to the PVP event. This will cause people to go nuts on stamina refills, make the participation for PVP go through the roof, even for syndicates who normally don't participate, and once everyone has enough uzis, they will use more gold reloading raid boss stamina.
The only downside is you will have fewer upset customers, which sometimes seems to be your goal.
As payment for this brilliant idea, I would like the right to name the top award given to the #1 syndicate in PVP.