I have many suggestions:
1: If you are going to bring in d3 equipment bring them as rewards for achievements in game, and in a timed basis, if players have access to d3 gear they will just destroy the game with ease. Possible events could be: duel competitions, time attack competitions (who does x thing the fastest), maybe staging competitions (who can stage the pet of the week to the highest degree maybe), you get the gist.
2: Buff pets, or petclasses in general, while 8.1 is probably the best Masterclass patch in rappelz, its no lie that petclasses outside of BM are doing really poorly, and thats because while the main characters got a huge buff (masterclass) pets remained the same since staging was introduced, my suggestion is to add pet only buffs to an npc, they need ACCURACY immediately, its almost impossible to build a pet that can attack butkah, maybe just stuff like siren and harpy.
3: have an incentive to donating for the first time: my suggestion is Rudra earrings 2x unity earrings and the cloak for a week on the first purchase.
4: 100% set up a discord server for the server.