>>531186957
More animations to the L2Ds. They should be different depending on where you tap and their current bond level. It should have new voice lines as well.
More stuff to do in the Outpost. For example, the cafes and shops in it should passively generate credits, the generator, armory, and library should generate battle exp, etc. You can also invite a Nikke or two to the hotel for some heavy advise sessions
Buy a ring, "marry" your nikke, and level up their affection rating to even further increase their stats. Their voice lines should also change to reflect their updated status.