The Seahawks OL was one of the youngest in the league last year. They should get better just by progression and growth next year, although it's super trendy here to just bash the hell out of them and wallow in the misery. Yes, the FO gambled on young talent producing in many cases their first year. Yes it was a bad gamble with no real backup plan. But it doesn't mean they will be miserable next year, although there will be a learning curve (again) as they add new players.
Ifedi is moving back to his natural and college position of Tackle. He's too upright in his stance to be an interior lineman, but Tackles are more upright in their stance naturally, and he has the athleticism to man the edge. We'll see a learning curve again as he adjusts to edge talent in the NFL, but it should be an upgrade from Gilliam.
Joekel can be league average, which is really all we need. League average isn't good enough for a guy drafted 2nd overall, but with less pressure maybe he can be there. Also, Jacksonville isn't known for developing OL talent of any kind. Any OL that has produced there has been a veteran FA pickup.
We can expect Britt to be better in his 2nd year at Center. All we really need is a competent RG and to see progression or an upgrade at LG. Problem is, we're looking at a new RT, new RG, possibly a new LG, and a new LT. Yeesh.