Create a new material similar to the Ascendant Shard that is very difficult to attain and requires a lot of grinding but allows the player to bring across the one (or a few) select guns that they consider god rolls and love. For example, I have a Galliard with Kill Clip, Outlaw, High Cal and an SRO-52 scope that I have over 2000 kills in PVP with. This is it's last season. Allow me to be able to carry that to a subsequent season light level using this new material. Put a 3 or 5 weapons per account cap in place. Everyone will stop complaining as long as they can bring one or a few of their favorite guns into subsequent seasons but they will still grind for the new versions. I'd imagine some guns like the Pinnacle weapons would be restricted from this as the intent is to sunset perks not just weapons. But if some weapons are keeping similar rolls, allow them to be buffed to a higher light level cap using the new token/material.