I figure this is the best place to put this, even though it is more about anticipating future appreciation of Gronk, say around 10 pm Sunday.
In 2013, Seattle lost three games, to Indianapolis, San Francisco and Arizona. Fleener caught 2 passes for 15 yards, Davis caught 2 for 21, and Arizona had 2 TEs combine for 4 catches, 33 yards. That doesn't suggestion a TE running wild is a key to beating Seattle. When they played against top tier TEs, Greg Olsen had 5 catches for 56 yards, Jimmy Graham had 3 for 42 yards, then 1 for 18, Tony Gonzalez had 3 catches for 29 yards, and Julius Thomas had 4 for 27. The Seahawks won all of those games.
In 2014, Antonio Gates torched them, 7/96 as Seattle lost. Then Witten only caught 2/24 as Dallas beat Seattle. Kelce went 3/37 and Cook went 3/25 in two other Seattle losses.Greg Olsen, who did some damage in 2013, went 1/16, but then 5/58 in the playoffs. I am sure football central will be able to do a lot more (if they think it's a key to the game), but it looks to me as though TEs can get decent yardage, even if the overall volume doesn't suggest covering the TE is a problem for Seattle.
That encourages me that Gronkowski, a better TE than Seattle has faced, can do slightly more damage (both in volume and yards/catch), and it can come at the right time. And, if a Seattle defense that is typically decent against TEs takes steps to reign in Gronk, that may open things up for others.