Walker was one of the biggest trade chips we had, and he's gone. Can't weaken the starting rotation any further just to add another starter, so Paxton stays. Iwakuma has no value, Diaz has too much to us. Nobody wants our rafts full of 4th OF, and Marte's already been swapped. We don't have a lot more #1 picks to sell like Jackson. I've said before that one of the benefits to drafting teens early is that if they don't pan out someone will still think they have time and are just late bloomers. It's easier to sell someone on 21 year old Alex Jackson than it is 25 year old DJ Peterson.
So Seattle's major chips on the farm are Gohara, Neidert, and O'Neill. Lewis is injured and as a draftee last year he can't be swapped til the draft this year. Same with Rizzo. All the young, low-minors arms are gone now (Littell, Orozco, De Paula).
Hard to do better than Fister in trade, IMO. Not unless you burn the farm to the ground. I see MLB.com still has SS Drew Jackson as our #3 prospect, though. We can cash him in at that value - I'm all for that.