In the Easter event, I've been having fun running Victor the Vicious, which I don't do normally as the payoff is better on Black Knights. However, since VTV is one of the ones with x3 loot, it's worth doing.
This got me to thinking, there are quite a lot of adventures but we mostly only run a few, which have a good cost/return ratio. The others just accumulate in a pile - partly, I'm running VTV because I had about 29 of them in star!
So here's the suggestion: Every weekend when there's no event on, pick one or two adventures at random from the list, and make them return 3x rewards. Run it for maybe 36 or 48 hours, so everyone gets a chance to do it. If it was 2 adventures, it could be one lower level and one higher level - split it at say player level 35 or so.