I agree with Kiper 100%. I don't think he said anything in error, though it is funny coming from him.
At Boise State, Chris Petersen dominated by bringing in 2 star recruits and turning them into NFL players. That's a amazing, but it doesn't change the fact that those guys he recruited were weak prospects. Had they gone to almost any other program, they probably are an afterthought. It's not the players that he picked, it's what he did to coach up and support those players.
Pete Carroll has pretty much done the same thing in the NFL, which is ironic since he regularly had the best recruiting classes in the nation at USC. This year Seattle drafted maybe their weakest group yet, the highest NFL.com prospect grade for any pick Seattle ended up making was a 5.4 (Norwood). Those grades were assigned before Seattle drafted those players. Keep in mind that a 5.0 is a UDFA score, with 8 being the highest. Three guys didn't have any grade because they weren't expected to be drafted or signed.
If we didn't have an amazing player development system and coaching staff, we'd likely be screwed with a draft class like this more often than not. But that's totally okay for us, because we do.
And like Kiper says, Okung and Thomas aside, PC/JS have never drafted super-high rated prospects, but they grow them into pro-bowlers with perhaps the best player development system the NFL has ever seen.
And of course you can't grade today for how players will develop tomorrow, which is the main reason instant draft grades are silly. But everyone should know they are silly and just take them for what they are, a snapshot of what people thought at the time.
I just think this draft is interesting because Seattle still "reached" like crazy as usual but they didn't reach for the Tharold Simons, Bruce Irvins, JR Sweezys, or Korey Toomers. They reached for guys Tim Ruskell would have loved, polished players, mostly from big schools with high marks for character. Most of them seniors. It seems Seattle's player acquisition process is ever evolving.