Just had some quick thoughts about how to make kills feel a little more satisfying.
It might be nice if all the different damage types and skills had some more clear and exciting unique on-death effects. I think PoE actually does this decently to a degree, but it would be really cool to see your damage-type represented a little more clearly when creatures die. Damage types really need an identity, right now they all feel a little too similar when it comes to visual indicators and monster response.
For instance, let’s say you do Necrotic damage as your main damage type. When a creature dies or gets hit it would be nice to get a really clear and exciting indicator that you just killed it using Necrotic damage. They could melt as though they’re being consumed by acid, or they could have some really cool soul-steal type effect where their bodies have a green-fire and a little soul gets pulled up from the body and fades into the air.
Obviously, the on-death effects would have to be subtle enough to not fill the screen with visual clutter, but I think little details like this can infuse a game with life and excitement, and it can make killing monsters feel amazing.