I think you are understating Nelson's effectiveness as a coach. He has a track record from his days in the Edmonton orgnization for being good at developing young players. You also conveniently leave out the impressive season Russo had. Nelson seems to be a good coach and I think the odds are good he at least gets an interview for a head coaching gig.
Finally, there were clearly signs Blashill altered his approach as the team floundered early on last season. Everyone suggested the players needed time to learn his system, however as the season went on it was pretty clear they were moving away from Blashill's system after the advanced stats showed we were one of the worst teams in the league. If not for adjusting to a more defensive approach - along with no longer playing Kindl and Smith for huge minutes
- the team was able to limp it's way into the playoffs on the back of Petr Mrazek's dominant start to the season.
So like I said above, I am not being critical of the Houda hire. I am however very skpetical of Blashill's preferred system being able to purportedly turn proverbial straw into gold. Add in the fact Holland felt it necessary to get a guy to coach the defense who has tons of experience under Claude Julien and I am of the opinion that it is reasonable to question whether the Blashill style is something we can expect to ever materialize.
Cam Neely called Julien's style an attempt to "win 0-0 games". If we know our GM's only stated goal at this point is to make the playoffs and if your prospect pool is almost entirely comprised of moderate skiill guys who are known for their two way games well it's safe to wonder which system is more likely to achieve your GM's stated goal?
This is getting a big off topic so let me bring it back: Sproul is not a fit for this organization. There are at least two guys in a position to trade for him who are quite familiar with his strengths and weaknesses. My only real stated opinion on the matter is to trade him now rather than risk losing him for nothing or have him basically eat up a roster spot in Detroit while never really being able to fit in with the organization.