For the Bear Mountain section, the New York–New Jersey Trail Conference responded to thru hiker complaints by building what is essentially a staircase up the south side of the mountain. They also put gravel on the summit trail and by-passed a steep section on the north slopes with a lot of pointless switchbacks. The excuse they used was that they wanted to make this section more handicap accessible.
South of Bear Mountain, the AT used to descend West Mountain straight down east off the ridge, steep but still manageable. Now it continues north almost until the ridge meets the base, adding a lot of unnecessary distance.
Officials will give their own explanations, but these changes clearly seemed geared toward making the trail easier for thru-hikers. The new sections of trail offer no lookouts or viewpoints, for example.