While about what I d like to see next:

The gear stats and its balance:
Legendary sets with small procs on weapons and they are all dropping mobs MOBS in new maps

Set rarity items dropping from golden version of mobs (rare mobs, max 2 per map)

Mythic bound set that can be crafted with ingredients dropping from new maps (mobs and bosses) (the set granting special proc)

Arcane weapon dropping from the hardest boss of new maps (guess its Kraken) (elite maps if you add them)

A new pet with strong debuff skills (the best to kill kraken) dropping from Elite kraken himself, same as Arcane weapon

All others missing items will be added in locks during events