Half the league has more than 10M in cap space right now, and a quarter have more than 20M. The Caps can take salary back in the deal too, so they could do something around Girard with the Avs, Roslovic with the Blue Jackets, etc. Blackhawks fans here and on other sites have really let their imaginations run wild about cap dumps. A 55 point center who's one year removed from a point per game season and has a great playoff track record isn't a negative value at 7.8M for two more years. Look at the long term contracts that middling centers like Trocheck, Copp, or Strome got despite the flat cap last summer and tell me a center for whom 55 points is a major disappointment wouldn't get close to his current cap hit if he were a free agent signing a two year deal this July?
There's so much wrong with this it's hard to know where to start. Datsyuk was LTIRetired at the time, so the trade was done knowing he had literally no on-ice value, which makes him a bad comp for Kuzentsov. The bigger deal though is that you're conveniently leaving out that the Red Wings got the #20 and #53 picks back in that deal. Giving up the 53rd pick to move from 20 to 16 is pretty much fair value, which means the Coyotes took Datsyuk essentially for free because his contract was insured and they were using it to circumvent the salary cap floor. So A) Datsyuk didn't cost a mid-1st to dump, and B) his situation isn't relevant to Kuznetsov's anyway.