Hack/Mine has been 99% hack 'n slashing, and 1% mining. I'd like to add some more mining into it. And crafting, of course.
Only "Rare Mobs" (The one with colored skins and a name, having more health than its normal variants) will drop items, and all monsters will spawn in groups of 6, one of them beeing a Rare one that'll always drop a item with a prefix and/or a suffix and has a chance of dropping one without prefixes/suffixes aswell. Boss mobs can now be found in tower's Chest Room and they MUST be beaten or the chest can't be opened. The boss mobs will always drop a Rare item (3 prefixes/suffixes), 4-6 scrolls based on the area's level and will grant access to the chest. Dungeons will have LOTS of boss mobs, one for every room with a chest, but in the end of the dungeon, a "Epic Monster" will be found, wich is REALLY powerful but worth the fight, as in the last dungeon room, a double chest (also locked) will be there containing the best possible loot for that level area. The Epic Monster itself will also drop 20-32 scrolls, 3 Epic Items (4 prefixes/suffixes) and depending on wich mob it is, a crafting recource.
The Boss Mobs would all just be bigger variants of the regular mobs, having 25x its health and doing 10x its damage. The Epic Mobs aren't anything like average monsters, there'll be different possibilities, mostly based on area level. In lower level areas, you could have Arch-necromancers, for example. These'd summon skeletons with the same level as the area and cast life-stealing Cursed Bolts at the player. On death, they would drop Eclipsing Dust, wich then is used to craft Runic items. Or Dragons, of course. Dropping Dragonscales or Dragon Bones and thus only beeing in high level areas. Or maybe the allmighty Lord Herobrine himself, in level 100+ areas? The possibilities are endless.
As some items are made out of Copper, Mythril etc. , those ores should appear in the ground. Stone should be able to mine iron again, too, and mobs have a chance to drop pickaxes or shovels, wich can be repaired and have stats on them.