An idea for exotic coin.

[ArasDorvay]

In exotic shop, there will be a time machine. Costs an exotic coin to get you in the year of exotic shop that you want.

So basically, for 2 exotic coins you can purchase previous years items.

And for 1 exotic coins you can buy current new exotic weapons.

[Grief Hero]

Don't really see this happening.
Exotics are meant to only be available exclusively for one year, with a limited amount being sold per year.
Sort of defeats the purpose if you can go back and buy them, even for a higher price.