So as most of know, Luke Smith has confirmed that Elemental Primaries are being "Left Behind" because it would remove weapon diversity but I don't think we have to rid the game of Elemental Primaries all together. Instead add an item the will drop from the raid which I call "Elemental Cores" there will be 3 like usual a solar, arc, and void and what elemental cores do is that you can infuse the core into a primary weapon with kinetic damage and give that weapon said type. But elemental cores will not work on exotics and only for year 2 legendary weapons.
Example: If I were to take my Smite of Merain pulse rifle and use a solar core on it, I would then have a solar Smite of Merain. But if a friend of mine has an Arc Core and a Hung Jury SR4 he can then infuse the Arc Core into his Hung Jury and give it Arc Burn.
I think this would be perfect because We will still have weapon diversity and still have Elemental Primaries.
Feel free to ask any question about this topic. ^.^