The problem with making cash the only way to get old weapons is that now that there are several “required” weapons (Earth’s Fury, Yasmine’s Pride, etc.) it could be argued that there is effectively a paywall in place. I’m sure there are people willing to drop $5 on a weapon, but that shouldn’t be the only way to get them.
Whatever solution they’re coming up with really should have an option that doesn’t require a real money payment. Whether it’s a Soulforge recipe or a mountainous grind or a flat Gem cost doesn’t matter. Offer a money option too, but leave the door open for F2P players. Nothing that can impact a player’s performance during a match should be exclusively paywalled.