2016 is not a midterm, unless Republicans somehow changed the rules when no one was paying attention, so that doesn't exactly equal easy win for Republicans. I would bet heavily on Democrats holding it.
Excellent news! Dem chances of holding this seat increase without the albatross of Reid's godawful approval ratings.
Both Sabato and Rothenberg agree that this seat is more vulnerable without Reid. Let's face it, if Masto doesn't run, the rest of the dem bench really sucks.
That's not surprising they think that. "muh incumbency"
But in reality, Reid's deep unpopularity was going to cause significant crossover against him provided he faced credible opposition. Masto won't start in such a hole. The bench does look extremely thin after the 2014 wipe out, but since Masto is likely running, it shouldn't be an issue.