Isn't Ayotte reasonably popular? PPP had her up at 49/32. She seems fairly liked in New Hampshire and was reappointed Attorney General by a Democratic Governor, John Lynch. Given she probably would run ahead of the Republican ticket, she seems one of the safer incumbents facing re-election.
So was Shaheen at this point.
Shaheen similarly survived, but that was a wave 2014. I don't expect 2016 to be a wave.
New Hampshire probably reelects Ayotte, if they don't, New Hampshire cements itself as a Lean D state.