Lindblom got demoted both because they wanted to get JVR with a better center (they were spending a lot of money on him) but also because he had a cold spell where he was trying to do too much, you see that with young players all the time, TK especially, they start pressing and get out of their game. Veterans get more patience b/c they've shown in the past they can get themselves out of a funk (or they wouldn't be veterans, they'd be in the AHL).
One advantage on the 4th line is you're there to forecheck, there's no pressure to score, so it lets a young player "just play" and stop overthinking.
With Lindblom, we're seeing the game slow down for him, he's no longer trying to score too quickly and blowing scoring chances - and that's where advanced metrics come in - they're basically predictive metrics, so when someone like Couts or Lindblom has great advanced metrics, the scoring usually comes at some point, When someone like Weal has good advanced metrics, but the scoring never comes, well sometimes the numbers lie.
Actually, what you're probably seeing is the player is setting up opportunities but lacks the skills to close the deal.