I believe that most veteran players can recognize the tedious grind of farming. Especially on the maps that you will beat even without a full team of five. Loot tickets is the obvious alternativ for that problem but here I would add a second option to that.
If your team strenght happens to be over 1000 more than the monsters on a a particular stage, then you would get access to a “Boo!” button that make that level to an instant win, just as the loot tickes work. This will be based on that the monsters on that stage have turned into getting scared of your mighty team instead, and are now fleeing the stage. This would be a practical and fun meta challenge that encourge even new players to one day unlock their first “Boo button” oppertunity.
Some maybe think, “But then you dont need loot tickets anymore”. Loot tickets will always be what the majority of people want, since that gives access to farm all over the maps where it is most needed. What the Boo button would add to the mix, is to inspire the player to unlock more stages with the Boo button access and also take some of that tedious grinding pressure off the commited player who else are at an increased risk at getting tired with time by the exceeding grind. The Boo button would add to the appriciation of ones growing team strength and inspire new players to unlock this meta level instead of the exceeding grind that adds up with every leveling up.
Keep the fun where it belongs!