So, you two are arguing about two different use scenarios. Rongways suggestion of visible duty completion in DF has been, since beginning, for full parties only. This clearly includes first forming the said full party, most propably through PF. In this use scenario, it is reasonable to say that the RF doesn't add anything else to the table.

However, the use scenario Dzian is going after is one where solo player can queue into random party finder with the comfort of knowing they get into a party of those who have completed it. This approach would skip the forming of the farm party outside of the finder. In that use case scenario the suggested feature to DF would not give any results.