I participate in a 14 man redraft league and have been for the last 11 years.
Trading draft picks can be an effective tool in the draft. It is by no means CHEATING or UNETHICAL. Why would anyone think that?
I will tell you that trading picks really should ONLY be done during the draft. How else are you going to know what you are getting or more directly, WHO are you getting.
Trading draft picks is the most effective when used with tiering. Tiering is the grouping of players with indistinguishable value of the same position.
I will use an example from my draft last year. I had the 13 pick in my 14 man league(Snake style). After securing 2 RBs with my first 2 picks I assumed I was going to go WR with the 3rd. I assume this because I know my league and if I wanted to go RB again, it would probably be my 25th ranked one. So as the 3rd round progressed I tried unsuccessfully to trade up and grab that last running back(Just too big of a jump) I had in one of upper tiers. So I then worked on grabbing one of my WRs from my second tier of WRs. This tier of WRs included Moss, HOlt, Ward, Moulds, and HOrn. As the round progressed I finally found someone who was willing to trade. We switched 3rd, 4th round picks. He then wanted a sweetner because moving up 7 spots in the 3rd round is a much more valuable than moving up 7 spots in the 4th. I offered we swap 8th round picks, he said 6 round, I then said 6th and 7th. He agreed.
I then selected Hines Ward, the last WR available at that tier. And the rest is history the guy had another great year.
So the question is when do you trade. Well remeber you can trade UP or DOWN. I traded up because I felt that I could get a guy (HINES WARD) who was the last of that upper tier. If I just sat pat I would have had to select a WR that was in a lower tier.
SO the rule of thumb is, "TRADE UP TO GET ONE OF THE LAST GUYS IN A HIGHER TIER".
So now when do you trade down? Well I think we all can figure that out. "Trade down when you think you are going to grab one of the first players in your tier."
If you tier players, and they all in your mind are equal, then why would you want to be the first one to select from that tier. That means every time you select you are getting the worst value.