The facts of the matter are:
1) Demarcus Cousins is arguably a top 5 player in this league
2) The Sacramento Kings have been an absolute mess since Cousins got there
3) After all the years, Cousins is still in Sacramento
One thing about Cousins - you don't ever really hear any former NBA teammates criticizing him. Guys in Minnesota criticized Love for his lack of leadership while he was with the team. Ray Allen criticised Rajon Rondo when he left the Celtics, and Doc / Ainge have both commented on him being at times hard to coach. Kevin Love and Chris Bosh made comments about how hard it is playing with Lebron. Countless guys have commented on how much of an unpleasant person MJ was to play with.
Yet none of the guys who leave Sacramento ever seem to complain about Cousins being a bad guy, a bad leader, or any kind of locker room issue. Isaiah Thomas still seems to be good friends with the guy.
That, to me, kind of hits home the belief that Cousins probably isn't a bad guy at all. He's probably much like KG - somebody opponents hate, but teammates love.
I read about him calling a players only meeting after the Spurs game - there were quotes from him saying something like "I have no problem with any of the guys on this roster" and "us players need to stick together".
I don't look at Cousins and see a guy who is a troublemaker - I see a guy who is fed up with loosing, frustrated with the team staff (specifically coach Karl) and who is trying to stand up for his teammates, who probably all feel the same way. I see him as a leader - a guy who is standing up and taking a stand to speak out on behalf of the other guys on his team, who (themselves) might not have the balls to speak out.
I love the guy, and I don't know if there is another star player in this league who personifies being a Celtic like he does. He plays hard, he's tough as hell, he's physical, and he's not afraid to speak his mind. He's basically like a 6'11" Rajon Rondo without the excess cheek.
Oh and yes, I would trade the Nets pick for Cousins every day of the week and twice on Sunday. Every GM in the league would. Even if you had a pick guaranteed top 3 (which the nets one isn't right now) you'd still do it without a second thought.
If you look at his stats at his age, compared to what historical players put up at his age, Demarcus Cousins is on the path towards being one of the greatest big men to ever play the game. There is no big man in the past 20 years who put up numbers better than Cousins is right now (at the same age). One or two were about on par, but none better.
The guy is an absolute beast. Put him in an organisation that makes sense, with a coach who respects him and appreciates him, and he'll work miracles for your organisation.
Also if you don't believe in his impact, take a look at the Sacramento King's win records when he isn't on the court over the past 4 years or so. Without Cousins the Kings would have been last year's 76ers for the past 4 years.