My opinion is different. I highly doubt BioWare will do anything new to Neverwinter Nights. I think the chance of NWN attracting new players after the release of SCL is much higher. Not everyone's gaming preferences are so shallow that they'll refuse to try out an old game altogether. Let's be optimistic.
Time will tell. But I know how hard it is to hook newer players to older games. One of my university friends, for example, was a vivid Starcraft 2 player, it was pretty much the only game he played 90% of the time. I was a bit shocked to learn that he had never played Starcraft 1, and I highly recommended it to him. He bought the game, tried to get into it, installed it a few times, started playing, then uninstalled, then installed again... He just could not get past the outdated graphics and mechanics.
I myself could never really get into Baldur's Gate series. I started playing RPGs in 1999, and I played only 3D RPGs till early 2010s - hard to say how it happened, but I managed to miss all Infinity Engine games. Last year, I played through both Baldur's Gate games with all the expansions - and, honestly, the only thing that made me keep playing was the mental check I would put on this series after I'm done that "Yes, I've played this classic". I liked the character interaction, but, good lord... the graphics, the mechanics, the combat - everything was so outdated, felt so clunky, that only my extreme completionist nature saved me from quitting a few hours after I started.
And I have been playing video games since 1991, so it is not like I am not used to severely outdated games. Imagine how Neverwinter Nights will look to someone who started playing, say, in 2005 and grew up on games like Mass Effect, Dragon Age, Skyrim, never having played anything much older... Maybe NWN2 will look fine to them, but even in this I am not sure.