I've always thought this was unfounded. Yakupov's problems are substantial, not the sort of thing that just popped up because of his first NHL coach.
He looked good under Krueger, and also Nelson when he actually had a bit of a mentor in Derek Roy as his centre.
Do not underestimate the toxicity that Ekains brought to that team after Krueger left.
One of the biggest issues for Yak (and the rest of the team) was that they were left to their own devices to improve. Zero mentorship was ever provided.
Hall, Ebs, RNH, Yak, and Schultz; like Gagner, Nilsson, Cogliano, POS, and Brule before them, where all left to fend and learn for themselves. Hell you could even date that back further to the team failing to control Torres and Stoll when they broke into the league.
Bad habits and immaturity where never things dealt with under the Lowe/MacT Oilers. Well...
unless Eakins' suit got wet.
When it came to leadership, management fell in love with tough guys who worked hard and set a good example, but didn't really do much to bring a room together (see Moreau, Horcoff, and Ference). The only "loud" veteran personalities those teams brought in (post drafting Hall) were Sutton and Hendricks. However, I think management actually avoided those guys, as they knew they'd be called out (see the spat with Souray)
Honestly for the topic of this thread, I'd be curious to see that entire 13/14 team had Krueger been retained and MacT not gone on a power trip thinking he'd re-invented the wheel.
It's the same story for the 08/09 team, which also featured a ton of wasted potential. Funny enough that team's falling apart was also due to MacT inability to manage a room.
*Rant over*