But if prestige modes do end up developing, having new skilling content would be lovely rather then the same old shit especially if you're doing it on a 1x mode if that comes. But even with that I'd take simple stuff such as tree farming and interface updates as lets be real a fair few of the interfaces are shit for some of them mainly the smithing one, alongside farming being buggy af. Obviously if you're on gamemodes like normal-hard skilling is already easy to point you can knock out 200m in hours at max, but if a new prestige mode below prime was added I'd rather actually enjoy skilling then wanting to kill myself over it.
As for zolcano sure it might sound pointless as crystal pickaxe but if anything it could introduce the divine versions of pots from crystal shards, or as with OSRS introduce the gauntlet weapons and the shards would be useful for them too