I would 100% love a Nightdive (or similar) remaster of Deus Ex. But my point is more that it really doesn't need it, mechanically. If you were to go boot up DX after having played nu-Prey or Shadows of Doubt or whatever, it would be familiar. Some rough edges but no more than going back to DOOM after... DOOM 2016. And SS2 (and Thief) is maybe one notch further than that.

Contrast that with SS1 where it honestly had more in common with what would become the mechwarrior games than DOOM (see also: CyClones).

As for funding: Plenty of indie devs have talked about it. Xalavier Nelson Jr is always a good listen (he did a few episodes of Remap Radio). Late 2010s/early 2020s, getting funding for a video game was, if not easy, very doable. That is more or less what let Nightdive establish themselves as the weirdos who go REALLY REALLY hard on loving remasters of older games.

But between economic uncertainty and the realization that COVID was probably a localized peak for the gaming market, it has gotten a lot harder for basically every studio to get funding. Which is likely why Nightdive seem to be doing every single iD/MS game they can or games that are part of multimedia franchises (e.g. Dark Forces).

So Quake 4 is a no brainer (would love 3 but that is multiplayer first which gets risky). And while Nightdive CLEARLY love System Shock (it is more or less what the company was founded on), getting the funding for a full "game" a la 2023's SS1 is a much bigger challenge than a ridonkulous source port/patch. There isn't a company that is really going to be eager to fund that because it isn't part of a major monetizable franchise (although Dommy Bug Mommy SHODAN as a Disney Princess would be peak dystopic hellscape) and there would be a hard sell in terms of it significantly increasing market share over the remaster.