d6 dice pools were used in the (very ancient) Vampire Quickstart booklets in early editions, in a streamlined version of the main system, I'm unsure if that system was used for the subsequent games' quickstarts.
It could be interesting and intuitive, roll dice, 5+ is a success, maybe 4+ for stuff you're good to, maybe penalized at 6-only if you are under stress/curse/magic/something.
It also could be used as a global initiative roll: roll a pool and each success is an activation, and maybe you can force more activations by taking wounds or something.