Not a fan of Fournier but do think the situation could have been handled better/differently. It's not like he was different defensively before he got here or regressed b/c of an injury - he's essentially the same player. It's fine if the FO wasn't on the same page with Thibs and brought him in anyway. It's also okay that he didn't make the shortened rotation as coach decides rotations, etc...
We should remember that Fournier signs here assuming the FO and coach are on the same page and Fournier thinks he will play (since the Knicks sought him out and paid him well). That can contribute to being pissed off 2 years later when you're pretty much bansihed to the bench when you're thinking of your future opportunity for a next contract. Hard to get that if you don't play/earn it.
What could have been different is that if the Knicks decided he was no longer in the plans and they wish to move/trade him - then you can't let him rot on the bench eternally and expect you will get a fair value return in a trade. IMO they could have played him some minutes here and there to show other teams what he does well (along with the fact that we struggle shooting from outside) and maintaining some type of positive relationship while you shop him. Easy to cite the Heat as they didn't play DRob and Herro at times due to their defensive limitations - but used them when needed (instead of outright banishing them) and they both still have some value - which will prob land them in Portland for Dame.
The problem to me goes back to Thibs stubbornness ("my way or the highway" philosophy) and/or the FO and coach not being on the same page. While it may be a shared responsibility between both parties I think they are now paying for their own mistakes and should do right by Fournier if possible.