As did Leonard.
He was very, very good last year 2015-16. He became elite this past year.
If you want me to say KD is better than KL, I will, but marginally so imo.
KL, to be fair isn't playing with the caliber of teammates that KD is. I don't hold that against KD, but when you have Curry and Thompson to draw coverage away from KD, where they can't really double team, then you saw that results. He was spectacular, but I think you're downplaying the leap Leonard also made this past year from all star top 10-15 player to bonafide great top 5 player - an admittedly subjective ranking, but nonetheless Leonard became a great player this past year.
KD was the best player in the league this season.
KL wasn't too far behind. That's my opinion. I'm a Spurs fan, so I admit my bias, but those are my honest evaluations. If this was the KD of today vs KL of 2-3 years ago, when he won Finals MVP, then I'd agree about KD being on a different plane.
I think they're both on that same plane today.