the reason you wouldnt likely do that is because I dont think he drops that far in the majority of drafts.
I'm sure it happens, but the odds of him being on the board at 11or 12 is likely less than 50%
and if you are drafting at 7 or 8, the real issue is if you dont take him, you wont get him. Thats where it becomes more difficult.
in some leagues Im sure the trade back option is there. but in a lot of leagues there is no trading of draft picks so I'm not sure your option works for most. in the draft I'm gonna be in next week I do have the ability to trade back. I just dont know that I will. I drew the #5 draft slot. I dont see myself trading back.