I think we should be allowed to trade future picks, but I also thing there should be no roll over.
The name of this game is to try and predict/build a specific team and see how close you get to how the real world goes.
Once next season happens, you revert to the picks said team has in that year. IMO, the interesting thing about this is what you would do/think a team should do, is actually what they do.
So yes to trading future picks, NO to that having any impact on the next mock draft.