There's no longer a reason to separate the slot weapon pools. The heavy slot is perfectly fine running all different energy types. I want to see two slots to pull from all non-heavy weapons.
We no longer live in a world where all Kinetic slot weapons are Kinetic. Both slots allow you to equip primary or green ammo weapons. A change would only increase the customization and the versatility of the weapon pool.
Maybe you want to pair a strand or stasis weapon with a Kinetic, or run an arc weapon with a void weapon. Maybe you want to equip a solar primary and a solar shotgun. I don't see how this would hurt balancing or do anything other than add to the fun factor.
Please share your thoughts.