Today when I was running some arcade with some fellow vanguards we got into a jelly farm and near its end we saw a locked part of the map and it made me think, why can't we just run through all of the jelly farm as we wish, and so came this idea that there should be a level that contains all of the jelly farm on one big floor.
It could either be bought with real money, energy or maybe a recipe that requires a unique material that can only be found in the slime casino. Or maybe a recipe could be purchased with energy that would allow you to craft a key to that level and it requires a number of that material that has a 1-0.5%-ish chance to drop from any wheel in the slime casino.
It should also come in tiers like OCH is and maybe there's a different blueprint for each tier key with the amount of that material doubled for each tier so maybe 10 for T1, 20 for T2 and 30 for T3.
This idea wouldn't only provide "new" content with minimal effort that would provide money like a regular DLC does but it would also encourage players to be more active since they have to go into arcade and hunt for the casino themselves.
Maybe the same could even be done with the jigsaw valley or other similar levels.