Word is, most people are converting down any currencies they feel they wont need in the future, creating a large pool of officer tokens for pots etc.. while you can still get more then 1:1. This is of course a small risk because Mythic could implement more things on the vendors for the mid level items like the talismans, so do your own research and weigh your own options carefully. See patch notes below.
Patch Notes:
Open RvR Currency Changes
With 1.3.5, players will notice that each of their Open RvR Crests have been renamed to “Ancient” Crests. These items are not the required currency to purchase set items, but will instead convert into 5 of their respective crests (e.g. Ancient Conqueror’s Crest converts to 5 Conqueror’s Crest). With this change, the price of armor on the Medallion merchants has been adjusted accordingly.
Crests now convert downwards on a 1:1 scale (e.g. 1 Invader’s Crest converts to 1 Conqueror’s Crest, which converts to 1 Officer’s Medallion). Additionally, all Fused Crests will now convert into 10 Crests. You will also notice that anywhere you were previously awarded a Crest, you are now awarded a stack of 5 Crests.New to the Open RvR Stores
New unique Talismans are now available from each of the 4 Medallion Quartermasters! These Talismans of Aptitude and Celerity can be purchased with tier-appropriate medallions, and last a certain number of played hours based upon their quality.
ps. In a somewhat related note, if you are testing on the test server and need to break down tokens fast to buy gear, there is an addon called mass refine which people are using to do that.