Reminds me of a slower Miles Austin, or maybe a MUCH slower Cordarrelle Patterson. Keenan Allen works very well as a comp too. Big dude with moves and YAC ability. I seriously doubt he is fast enough for JS given the bulk of his history drafting 4.4 and 4.5 WRs. He does have a lot of unique qualities and Seattle loves YAC, so maybe JS can make an exception here.
IMO, he's going to be a good NFL player. I don't know if he fits Seattle. The aforementioned JS speed requirement is an issue, plus Seattle throws the fewest passes over the middle of any team in the NFL, and Robinson is going to be at his best working the middle of the field or in other situations that provide him space. He's not going to be the type Seattle is looking for- the red line threat who scares defensive coordinators.
He could very well be the next Keenan Allen. But I think what Seattle really wants is the next Vincent Jackson prospect (Mike Evans), the next Brandon Marshall prospect (Martavis Bryant), the next Sidney Rice prospect (Jordan Matthews comes close). This is one of the best years ever to get a tall WR with size and speed, so I expect them to target that specific area of the WR group.