This in my opinion is a no-no. This is the main reason I stayed on Destiny, because I wanted to get better. Implementing the trade system would take out a large portion of the fun I experienced. In addition to that, it's too late to add this in. The forums will be loading crazy with complaints about how they've worked so hard for all their gear, and now some fakes are rising. The Vault system is useful enough, seeing those with 3 of the same class.