but what about like 70% to 80% gamers that play on console and can't mod
They'll either like or dislike it? (Also I find the notion that 70-80% of people playing TW3 will either be on consoles or won't be able to install a simple mod, kind of ridiculous)
Most open world games end up having relatively bright nights... Red Dead Redemption, TES Series, inFAMOUS, Arkham City/Origins etc, and I don't think it necessarily ruins atmosphere, it just doesn't add it.
Nights like in Dragon's Dogma or STALKER add atmosphere and immersion, but a "bright" night still can be extremely atmospheric regardless. You might miss out on possible atmosphere, but the game can still be very atmospheric anyway.
In this case, it makes even more sense than ever before, being that Geralt has that ability to see better in general darkness. Cat is only needed when something is REALLY dark, like a Cave or Crypt. Now admittedly it looks like they've also made interiors like caves too bright, and if so then I think that's a bit of a flub on their behalf, but I'm holding out hope that there's some scenarios (Like Crypts or Vergen Mines) where you heavily consider the use of Cat.
I've also said this before, but people forget the fact that nights weren't really dark in either 1 or 2. TW1 had darker nights than 2, but it certainly wasn't Dragon's Dogma dark, you could see absolutely fine no matter where you went and never really needed Cat or a Torch. Nights being the same darkness level as W2 doesn't really seem like a big issue, and the people wanting DD or STALKER levels of darkness seems a little unreasonable considering the series has never had darkness like that.