I think I'd be okay with a more open world a la MGS V as long as all (not just a few) were more like V's Phantom Limbs, Bees Sleep, Voices, etc. I wouldn't be against open world if (huge if) the missions themselves were the same, and the open world we just had some side travel/post-endgame stuff in between. Though, that seems fairly idealistic because it is that ever the case? MGS V, Dynasty Warriors IX, a lot of games try to do that and say, oh the missions will be the same we just want the space in between, but it always ends up changing the core mission design. I'd be okay with it I guess if the missions still felt like SC though I suppose... If.
That said, even as much as I love MGS V, with SC even more so it excels with some sense of claustrophobia from the darkness and dense linear* surroundings (*in the sense you have a clear destination forward, not necarisly than you have 1 or 3 routes). I may be okay with the former idea if it was either that or nothing, but ideally hope it just feels like a spiritual success to Chaos Theory. They can make a Wildlands 2 if they want more Wildlands, and hopefully if they bring back SC it's really going to feel like SC.