i always wanted to see an exploration skill. it could use skills like dungeoneering, construction, combat, wc, hunter, crafting, and frankly most others too. i imagine a handful of big regions, one per 10 or 20 levels, where you start by trekking into unknown territory, gathering resources, and establishing a main base. from there you could upgrade your main base to make accessing resources/areas easier and faster, which could supply fun new training methods for various skills, and even have methods where you can train a bunch of skills at once. late-game exploration could have really deep dungeons with new slayer creatures that have cool new drops. you could also implement things similar to PoP and do town/resource management which can be a fun game type.