I would agree with this for somebody who lives at altitude, but for those of us who live at an altitude of 250 feet, Colorado can be quite an adjustment. The trail is certainly mediocre for the first few days, but the process of gaining trail legs and getting acclimated to the altitude can be important.
But I'd agree that the only really nice stretches in the first 6 sections were the Lost Creek Wilderness and Georgia Pass. And, you are right, section 6 wasn't my favourite, and the impact of the pine beetle in that section made it much worse when I did my 2014 thru compared to my 2011 thru.