People talk here like the defense will never improve during Panarin’s time here. The same arguments for not signing him can be made for signing him.
His cap hit % of the team cap will reduce each year. Again if the team is not competitive by year 3/4 of his contract then Management and Scouting has failed. That is year 4/5 of the Rebuild. That means most of our prospects did not pan out, we did not move some of our young assets in a trade to acquire a piece to fit a need (such as defense), and they never added a defenseman or two to help stabilize it. Year 3 of his contract. That means 2 Offseasons went by and the team had no progress in any of those areas. Lindgren/Hajek/Rykov/Reunanen/Keane/Miller/Lundkvist - not even 2 of them emerged as solid defenseman to add to ADA and Skjei.
There's a lot to unpack with your post but I'm just going to address your first point. I'm not saying zero prospects emerge or players don't improve in 4 years. I'm saying the trajectory of a defensive prospect is longer than 1, 2 or 3 years for a draftee. And if you are looking for a defensively sound, 20+ minute a night top 4, four years is probably the bet.
Seth Jones was taken in 2013 4th overall. He wasn't a #1 dman until 2016 when he was traded into that position. He didn't thrive there until the following season. We are talking about a top flight, blue chip defender, probably as safe a bet as a draftee and it took him 3-4 seasons to be that guy. Now we are looking at our pool of lesser pedigree and expecting someone to exceed that trajectory. Its labeled as a failure of drafting and development to not be ready sooner than a Seth Jones.
Miller is at D+1 and his *ceiling* is at top pair. Not his expectation or likeliness, his everything-breaks-right ceiling. Lindgren is 3rd pair likely, 2nd pair ceiling. Hajek might be a top 4, reliable guy. Rykov, who could sign here, maybe stay in the K, so let's not get ahead of ourselves, could be top 4 but that was Bear gloves' projection. Kean is still in college, how can we peg him top 4 inside four years? Lundkvist, like Rykov, has not even played in NA. Here's another name: Thomas Chabot. Hits the ground running from our perspective but he's a 2015 draft pick. He's doing great, but it wasn't overnight. This is the best case scenario for our crop, D+3 year as top 4 regular. But we need lightning in a bottle twice.
You dismiss the possibility of finding a Panarin through trade or UFA in the future but then you think the front office will be failures if they don't find solutions on defense through the same means.
I see your plan as being rooted in best case scenarios, good fortune and convenient contradictions. I like Panarin, but there is a foundation still to be built and short cutting with UFA does not have a successful track record.