Iginla is not washed up, he is just only useful in certain situations. He still knows how to bury a puck with the best of them. Unfortunately he can't win puck battles anymore, his skating has lost a step, and his defense can be lackadaisical.
He is still a good leader, and I'm glad he is on the team but he does need to be separated from both Duchene and MacKinnon.
Realistically, he should be playing 3rd line minutes, with 1st unit PP minutes. getting anywhere from about 14-18 mins a night depending on how many PP opportunities we get. At this point in his career he is just not the all around player that he needs to be to be a top 6 player on a nightly basis.
Moving forward I think you build 2 lines around the combos of MacKinnon and Landeskog on one line and Duchene and Rantanen on the other. With decent younger top 6 caliber players that can do more than just shoot the puck well.
Duchene and Iginla are just not a good fit. Duchene was a point per game player the year before Iginla, with Iginla not even close to point per game. Now the past few games without Iginla he has 9pts in 6 games.