I have no idea if you can do this but just in case here are some ideas!
1) Rares can be BestInSlot, discussed in this thread.
2) Castle as an account progression tool
Upgrading castle allows you to increase gold cap and makes other buildings upgradable upgrading castle needs gold and certain materials (i'll go into this later). Your castle also has several buildings:
-bank (same like now, but with tabs and upgrades increase gold earned)
-storage (stores your materials, can be upgraded)
-crafting station (allows for creation of artifacts-they are a crafted only item that goes into a special slot)
-barracks (gives you tiny all dmg buff)
-academy (increases rewards from dailies and weeklies)
-auction house (upgrading increases amount of items you can list)
This game really lacks a sense of progression and direction, i feel like a homeless adventurer that for some reason is killing demons
3) Dailies and weeklies
Make several dungeonlike maps like the last two in act4, make say 20 different ones. Now make server give everyone same/different 3 randomly picked dailies every day. Same with weeklies, but buff the mobs and rewards.
4) Resource gathering
When going to gather, you basically enter a map which has a double lower chance for all items! How do we make mining in a game that only has killing mobs? Make an ore mob! You kill mobs until you get to an ore, kill it, get materials. You can also add that after killing an ore you get ambushed for more fun
5) Crafting artifacts
Same as upgrading gear but a bit different, make a bit fancier effect when crafting, make it have chance to fail, failing doesn't destroy or anything but just wastes resources. Crafting needs gold and materials. The materials are both rare items dropped from bosses and items from mining/woodcutting/etc. Every class has 1 artifact for themselves. This feature isn't suppose to be customization but linear progress and reason to keep playing.
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