Make a leaderboard based on timed runs done exclusively with new items and pets. This will incentivate people to run the maps also after earning the best tier, will incentivate locked opening (that not only mega plat spenders can afford) if some of the items are only dropping from them, will incentivate elixir and respec sale, will award player skills, will keep new item prices medium-high and last but not least will give an opportunity to be in the leaderboard also to not rich people, also to who has not much time because has a job or study.
Another suggestion is to make a special banner awarded to people that will do a run under a specific time (like hauntlet achievement) to give people that won't be in the leaderboard a consolation prize if they did however a good job showing their capacity to do fast runs

With this leaderboard sts probably would also gain more dollars because every player will feel to have an opportunity till the end and they will spend for energies and kits since the last day instead on the current leaderboard after only a few days the difference from number 25 and 30 is already huge and more time passes less really competitors for the lb there are, at the end they will be 28-32 max trying to be in top 25.

Let me know if you agree or not and why and if you like this idea