What if they condensed tokens from similar types of content and expansions into one type of token then added them to the currency tab?
So each expansion would have its own 8-man Raid currencies (both normal and Savage), 24-man Raid currency, and Trial currency (sans special ones like the Monster Hunter Trial).
Harder/Higher iLevel content would give more of that token.
For Trial mounts you can buy with 99 tokens, maybe you'll need a certain drop from the Trial in addition to the Tokens (the item could have a higher chance of dropping then the mount or maybe just always drops in the chest).