I've been thinking about this alot, Pokemon B2/W2 had some sort of achievement system. it would be cool if there was something to do whenever you get bored, the quests can be accepted via New NPC's on the map. for example a quest would ask you to catch a certain pokemon or go find a missing object and will reward you with maybe money or even some usefull items such as hyper potions or something. it would give the game an extra feature that wouldn't be hard to implement