Will also agree, I have used 2.25 NN up front with a Racing Ralph in the rear most of this year and while it was fast rolling I didn't feel I had good traction for technical climbs and would spin out (like on LT) as I am not a strong climber. I moved my NN to the rear and threw on a Schwalbe Hans Dampf 2.35 up front and the traction has been a dream.
I totally agree with you. I have run HD and NN 2.35 combo exclusively this summer. While it isn't a super fast xc combo, the confidence from the traction is superb on the hard pack trails in this area.