Here they set a 1440p resolution, so no problem for downsampling guys.
http://www.pcgamer.com/2014/04/08/here-are-dark-souls-2s-pc-graphics-and-control-options/
Thank you! Now I can finally go to sleep. I was very worried over this. Having the image upscaled to 1440p doesn't do any favors to IQ.
Though their phrasing "Resolutions up to 1440p are supported natively" does still make me worry a bit. I'd love to play this later in 4k when I decide to buy a new tv. I'll just assume they meant that that's the highest they tested.