I haven't done exhaustive research on this, but in looking back at some of the WRs who have made big plays against the Seahawks secondary this year, there's generally one thing in common...speed.
TY Hilton - From the right slot, Sherman releases Hilton to Chancellor who loses him; Hilton catches it in front of Thomas who over-runs the play; 73 yard TD
TY Hilton - One-on-one against Browner, Hilton ate up the cushion and blew right by him for a 29 yard TD; perfectly placed ball where only TY could reach it
Cecil Shorts - from the slot, faked an inside route, Sherman let him go and he took off up the seam for 59 yard reception (Thomas was late covering)
Jarius Wright - from the slot, Wright right fakes an out right and cuts up-field, running by Sherman (who reaches to grab him, but it's too late) for the TD
Jarius Wright - from the slot, Wright gets behind the LBs and in front of Thomas for a 21 yard score
Tiquan Underwood - from a stack formation on the right, Underwood runs across the field and catches a 20 yard TD (Thomas was late)
Michael Floyd - One-on-one against Maxwell outside, Floyd gets a clean release and Palmer throws a dime over Floyd's shoulder for a game-winning TD
There are other factors of course (like moving Thomas out of position so he can't recover as quickly) and other TDs scored against their defense, but the weakness definitely seems to be speedy WRs who can get by the first defender and make plays with the ball in the air. Something we don't have. Don't get me wrong, we have great big-bodied WRs with excellent hands and toughness, but we have ZERO speed to threaten downfield. Seattle plays us in a phone booth every time because they have nothing to fear downfield with the exception of Vernon.
IMO, we should take a long look at guys like Odell Beckham (reminds me a lot of Hilton, though a little thicker) and Donte Moncrief (much like Floyd); guys who you can move around, get free in the secondary and make big plays downfield.
[ Edited by GhostofFredDean74 on Jan 30, 2014 at 4:07 PM ]