By special bosses I speak of the monster in the swamp and the fire elemental in metrica province. Bosses such as these, in lower level areas, should give players more incentive to defeat them, and also keep track on their timers like they do for the dragons. I’ve never seen the swamp monster, not even once. I’m unlucky perhaps, but still. Its a shame that some content is not seen at all by some of the players or is simply not doable due to lack of people to beat the boss.
There are champion enemies lurking in some places in Tyria, without events and sometimes without even a chest behind them.
My suggestion? The big bosses will drop an ectoplasm when you kill them (perhaps that should be done for the dragons as well), with a chance to also drop an extra ectoplasm or 5 exotic-grade crafting material drops (powerful blood, etc).
Champions will simply have the second reward, chance to get either an ectoplasm or 5 exotic-grade materials. That way players will have more incentive to group up and defeat these tough enemies that are otherwise ignored most of the time because its simply not worth the effort to kill them.
Note that this reward will be a drop from the monster itself in case of champions, or in the reward chest (along with the other random rewards) in case of the special bosses.
The specific reward I mentioned is merely a suggestion, if you have other ideas for what the reward could be then feel free to share.