Well, the equipment you get from delves will sometimes disappear when you reload the game.
Having random events like that might work, but right now, the only 3 people I use are Maeve, Throm and Jax. Once you gear them they can do everything alone, and everyone else become useless. Maybe making more delves, but having them as only certain people can be used, and each delve has different drops.
Delves are too short, and micro managing every level means you can only send one team at a time. Maybe be able to send people out on quests based on timers and even with so many people you could even have raids that require more people.
Also a level up system for them would be nice. Maeve's training HP ability is actually too slow for runs, and their HP resets every run anyway making it pointless. Having the characters level up, and having level requirements for new dungeons and raids that open each run would make it more enjoyable to progress.
You have a good base here, but as I said it needs more. Just think about games you've played where you joined a guild, and then imagine this being a way to manage that guild. The members have so much more they could be doing.