Locks are the best answer to the farming issue. They use 30 min locks in STO and it works well to get people doing other instances. Issue with multiple currencies for bartering like in SWG is that getting things becomes gated by people doing instance x. If no one likes instance x and has their gear there is no incentive to do it. For example in SWG this was an issue as only an experienced and lucky to not have it bug on you group could do Exar Kun. Kept me from getting my jewelry set before I had to stop playing. If you use locks that are at least 3x's longer than the time to run the instance people will run other content. Also add +5 seals for solo joining a random instance through group finder and that will really fix the issue.
Welleg , Kelleg, and Gelleg - Crickhollow
WARNING: leveling a warden may cause you to neglect your other characters.