Funny that everyone's imagining these doomsday scenarios. The fact is there's no reason you can't have a redraft league that allows trading future picks. I know because I've been in one for years and we've never had any problems. If you're afraid of people tanking, put some things in place to prevent tanking, e.g. weekly cash penalties for the lowest scoring teams, consolation bowls that reward teams that play well even when they're out of the playoffs, draft order based not on reverse standings but on something that disincetivizes tanking, etc. Apparently a lot of people can't imagine how this is possible, and that's fine I guess, although it's strange. But the correct answer to the OP is yes, it's legitimate to allow future draft pick trades in redraft, as long as it's a well-run league. It's pretend football, if you can find 10-12 guys who all agree to a certain set of rules, there's no reason they can't.