Who said NV was strongest at 3:00 kill time? It's strongest at ~2:30 because the second use lines up with Bindings + Potion. If you want to use it a 3rd time at 3:00 then you can't delay the 2nd use to use it with Bindings and as I said before the opening burst makes up a smaller portion of the kill time which effects the overall DPS a lot. NV is probably better than HotW at 3:30 but not by a large margin like it is at 2:30.
Another problem arises that if you take NV expecting a 3:30 kill then suddenly you kill it in 3:00 because of extra upgrades since previous week or whatever then you just lost damage. I'd really only take NV if I knew I was going to be getting those ~2:30 kill times.