What if the LFG actively monitored the population of players within the system and gave extra Rewards to people who queued as the under-populated roles?

For instance, the ideal population (which can never honestly be reached) would be
1 tank for every
1 healer for every
2 dps for every
1 support.

But what if the ratio comes up one day as being short on Tanks and Healers? A common-enough issue, but no worries! Now, those who queue as a Tank or a Healer will receive an additional Plaque or Loot Chest, an additional piece of Platinum, or boosted Experience gain as the "Quest Reward".

The system would fluctuate over the hours and consider the populations of the adjoined servers, and would bestow the bonuses as needed.