>>48938868emeralds frontier had great atmosphere and gimmicks to it
facility is almost rouguelike shit and forces you to use mons that you'd normally look the other way for
pike is just fun, especially if you don't look up a guide on how to interpret what the maid says. Adapting to the different trials (trainer battles, wild mon corridor, status) is fun
dome is quick and fun since you have to choose 2 out of your 3 mons to battle and interpret npc's battle cards
palace is eh, plays itself and its cool when your mon randomly plays a match perfectly or clutches out against all odds at the last second
arena is badass and the point system can often lead to strategic decisions on how to play and what mons to bring
Pyramid is the fucking best, by far makes me the most salty that it never came back. Choosing to stay in a floor and bag items, risking to battle against a powerful trainer or wild is cool as fuck, and the atmosphere is top tier
tower is there whenever you need to have a break from the various gimmicks
X and Y had nothing compared to that, even the maison itself looks lame