"Would the mod need Ballistic Vehicles?"
I´d love to see semi-realistic vehicles with the Ballistic style of gameplay.
"What weapon gives you the most satisfying kill?"
The DB Shotgun up close is probably a winner already if that poll was made...
"Should there be a grenade launcher?"
I just can not manage to kill anyone or anything with the grenades.
"Should there be many different 'flavors' of armor vests?"
Make a little more complex system than a single pickup with 50 or 100 points of armor, maybe use a decreasing protection percentage instead.
That´s my ideas so far, not really creative enough in my opinion.