Thanks :) Pets is a great idea! I haven't thought about adding any yet.
And yes, Quests! I my introduce these in an interesting system, where you have to do the quest once on one Adventurer, then optionally idle to do it again after its been completed once. I'll make sure they aren't just "kill 7 rats"!
Boss fights is another idea I love. I want to focus boss fights to managing multiple Adventurers at your fingertips, if your'e skilled enough. If not, you can try and take on bosses solo. The combat isn't intended to be turned based like it looks now, but it will still be idle for where it needs to be, like training.
Thanks for your feedback :)