Regarding NG+, I'm on my third and ½ playthough now. My first one I played on "Medium", the second was on Death March, the "third" was on NG+ Death March, and my current and 4th one is on Death March only again.
Unless you make the game more difficult for yourself and dropping your nice mastercrafted gear (I personally started NG+ because I wanted more time with my cool looking gear) you'll have a SUPER easy time. I didn't even have the avoid blows until I met a Chort in Velen that (for some reason) 2-hitted me. Other than that it was such an easy playthough. You'll also have a shit-ton of gold and potions. So progression in those parts are kinda wacked.
I got to level 48 on NG+ (after starting at level 36) and I blew though the quests, I didn't die a single time (the Chort didn't kill me, he just did a HUGE amount of damage. Nothing Quen wont help against.
Unlike Death March normal where I got killed almost every time I made a misstep, which did add a certain feeling for killing monsters. It made me excited.
I didn't feel like I was getting rewarded because I was using my Ursarine sword and armor.
And for some reason (this might just be me not being too used to NG+) All the quests felt so confusing because of the raised level on all of them. If you like the game, I'd strongly recommend playing on normal Death March.
Although, if you wanna play around with diffrent builds. NG+ is a GREAT place to do it. Since you can distibute much more points then you can in non-NG+.
But, alltogether. Witcher 3 is a fantastic game any way you play it. Seeing the crones for the first time gave me the same "hateful" feeling in NG+ and normal. And there is something really cool about wearing that Ursarine armor in Velen, you feel like such a badass.
PS. Does anyone know if scaling mods like the one linked before causes any issues with anchivement or gameplay?