I'm boring (it's literally the game in my avatar), but I think FF VIII would benefit the most. Hell, many of the design choices in VII Remake would suit VIII as it is, especially with regards to combat. To the point my post will seem derivative.
The OG is flawed (still one of my favourites ever by far), so a remake could potentially solve some of the narrative and gameplay problems. There are also a few some plotlines and characters that I think could be further expanded. Hell, some of the "subversive" stuff FF VII Remake did would fit this game really well thematically.
Its world is my favourite in the series, both aesthetically and lore-wise. VIII's towns are the best in the series imo (beyond specific stand-outs like Midgar, Junon, LINDBLUM...) in that there's a good amount of them and none feel out of place or boring. They all have a contemporary cozy feeling that would look amazing with modern technology (and, beyond Esthar and Deling City, all of them seem to be small enough):
When it comes to the character design, they already fit the realistically proportioned "anime" look FF VII Remake goes for (look at the CG models, especially). Which is one of the thousand reasons why Dissidia/Remaster Squall is so fucking awful. It'd be damn easy to make this cast look faithful and feel right at home with a similar aesthetic to VII Remake or, really, the latest FFs:
Gameplay-wise, there's a lot you could do with an update of the GF/drawing system and, regarding combat itself, the characters would already fit a VII Remake-like combat system (imagine having to time Squall's trigger presses while he attacks à la Nero). And, of course, imagine giving this game's OST the same treatment.
I'm a hypocrite, since I always want either new games or new IPs, but I'm sad that this will most likely never happen. It wouldn't be an endeavour as big as VII Remake (as VIII is considerably less popular), but it'd still require a huge budget, timeframe and, ideally, more than one game, so yeah.
With regards to Parasite Eve, Soul Reaver... I'd like new entries, but I don't have any trust in them making justice to the series. And yeah, a Xenogears remake would be glorious, but I don't have any confidence in that front either.
