Please go ahead with this plan but please put 5,000 PED of universal ammo on the vendors for 1 Rare Token during the period tokens are tradable. Simultaneously DON'T put any universal ammo up for regular Mayhem Tokens or for any other "payment" option related to Mayhem. ONLY Rare Tokens should provide an ammo "cash out" option.
Also, please be sure that the "vendor restocks" happen AFTER the token trading period is over and that if any UL token prices are going to change for the restock period that those changes are published to the vendors BEFORE the token trading period begins.
Many of the holders of Rare Tokens just want to "cash out" the value of those tokens to make up for losses they suffered during mayhem. I think Mind Ark should let them do that directly. This will greatly diminish the number of extra Rare Tokens floating around without forcing extra UL items (or any items) into the game. This will leave the remaining Rare Tokens in the hands of the yearning masses who would never cash in a Rare Token for any amount of PED and are just hoping to "earn" just 1 great addition to their otherwise mediocre arsenal.
Finally, if you actually want a transition away from UL weapons to more (L) weapon use, then those (L) weapons should reliably give higher loot returns than their UL counterparts. At that point they would actually be worth using and at least some hunters would use them exclusively. Right now most UL weapons top out at 94% or so efficiency, unfortunately there is one 97.2% UL weapon. At least for mayhem weapons it should be changed so that all the (L) weapons have a bit more efficiency. Maybe 10 or 20% of the distance to 100%. e.g: for
A&P Series Mayhem LP-120, Perfected (100 - 95)*20 = 1% higher for
A&P Series Mayhem LP-120, Perfected(L) or A&P Series Mayhem BC-80, Augmented at 88% becomes A&P Series Mayhem BC-80, Augmented(L) at 90.4%. This will give a real and meaningful incentive for (L) item use. (And frankly I think the concern of (L) vs UL is a separate debate from "too many mayhem tokens". No matter WHAT reward is given for mayhem tokens they will have to have a high value and may flood the economy. Avoiding that is very easy by directly giving the high end players what they want: More ammo cycle) Additional ammo will NOT flood the economy and on top of that as we learned when it was introduced universal ammo has a "0 accounting value" so it's kind of a zero sum gain by one viewpoint. POSSIBLY this may depress loot returns or unbalance something in the loot equation for a short time, but the loot return cycle has been the most resilient and long lasting mechanism in an RCE game for over 20 years. I think the loot cycle can handle it and was built to handle it. (To avoid "single first day" problems, ammo option could restock 2 per day or some such value and just continue until people stop emptying it over say 1 week)