If you want to entice leveling players into doing something, there's nothing they want more than exp so... I think the in need bonus makes sense. That said I'm not sure how effective it is.

Nothing they do is really gonna help the problem a ton. The damage was done when they decided to make parties groups of 4 people instead of 5+. Adding one more DPS slot alone could have cut the dps queue we see today down by around a third.