Adding a temporary currency that we collect inside echoes as we kill monsters and once we collect a lot, we can spend it to juice a particular echo of our choosing. And once you reset that particular monolith, the currency is wiped and you begin collecting again on the fresh one. I think that would be cool! It would really make killing the monsters in the echoes feel rewarding. It also gives you something to look forward to as you are going through your echoes. Maybe you didnt’t get the drops you wanted, but you at least have a mega map or two to have fun with while completing your monolith. And these particular maps will not only be more fun to play, they will also be more rewarding. Also more challenging! I think it would be a ton of fun and really ad some much needed spice to the monolith.
Each monolith would have its own currency pool that can only be spent there and is wiped when you reset that monolith. It would also encourage people to explore the depths of their monolith web to see how much currency they can collect and how crazy they can make an echo.