Because of the nature of the game and how quickly enemies are killed, the way that elemental damage is handled now is really not all that helpful.
What I suggest:
1. Elemental damage that activates instantly, as soon as the status is inflicted. For example with a fire-based gun, if I shoot an enemy and they get caught on fire, have them IMMEDIATELY take damage, not a few seconds later.
2. Make status effects like this shorter but more powerful, again, because of how short battles tend to be.