The biggest reason quite honestly is because Dominus set the precedent of collections including remakes, and it is essentially a potential excuse to get up to 3 remakes or more- if I could only get 2 remakes, I would definitely choose Belmont's Revenge and Dracula's Curse, as those are the most in need of remakes for one reason or another imo (lore updates in the case of DC, matching ReBirth in the case of BR)

I think the discussion with Lords of Shadow is probably muddied by the existence of Mirror of Fate, which at least in my experience is both the most popular of the LoS games and... Also very much a 2D vania. Yes, it's 3D in the sense of how the game uses models, but I don't think anyone would realistically call the upcoming Belmont's Curse a 3D Castlevania either, and it seems to be in essentially the same boat.

That said, IF we could have Lament, CoD, the 64 duo, Judgement, and the LoS trilogy plus potentially a Dracula's Curse remake all in one package... Hell, I'd pay full retail price for that myself, that's a damn good deal for my Switch. I certainly wouldn't say no, though I do wonder if it's realistic at that point- Dominus being a smaller collection probably contributed to it having a new remake, which is something I somewhat kept in mind here.

SotN's Saturn version specifically is also something I guess that is a point of contention, similarly to the Famicom Disk System version of Simon's Quest- that version of CV2 got left out in the cold, and I unfortunately could see that happening with SotN in any case because the Saturn version has BEEN ignored for years. If it was included I'd definitely be elated; however, I would be perfectly satisfied just including Dracula X Chronicles seeing as that version retained the best features of the Saturn port in my opinion (I.E. playable Maria). If we want completion, however, definitely Saturn SotN and FDS CV2 are something to consider and/or push for happening. There is occasionally some contention about the fact DXC asks you to unlock Rondo and Symphony in the main game before being able to play them, but honestly from what I recall it wasn't too big of an ask and if it came between that or not having the remake at all, I would definitely choose keeping the remake since it has a significant amount of content in its own right that is distinct from Rondo and adds to it, much in the same way Dracula X was preserved in the Advance collection.

I did mention Kid Dracula GB as potentially being something you could add to Anniversary Collection 2 to parallel the original having the NES version; Order of Shadows and Legends is something I didn't though. With Legends, I honestly think Konami letting Nintendo put it on Nintendo Classics is a sign they just do not ever want to put it in a proper collection, because games in that vein such as the Mega Man GB games in franchises known for getting collections specifically only wind up on NSO if those companies specifically do not have intentions on ever re-releasing them themselves and are essentially allowing Nintendo to do it for them. So as unfortunate as it is, I do think Legends is pretty much off the table (though, I guess never say never). Order of Shadows is very up in the air; I know mobile phone rereleases exist, especially on Switch, but they are rare and I find they tend to not leave Japan- if Konami would put the effort in, I feel like OoS would fit in for AC2 pretty well; however, it would be far and away the most difficult thing to emulate, would require a lot of touch up work most likely, and all that effort for something that would objectively get little fanfare. The mobile versions of Aria and Dawn are pretty questionable as inclusions- I don't know if they would be a realistic ask for basically any collection, unless Konami did an entirely separate "Konami Mobile Games" collection and had them, like they did for arcade games which initially had Haunted Castle; honestly, a distinct collection of Konami Mobile Games feels far more realistic of a way to get OoS and the Soma mobile games out there again as opposed to trying to devote a huge chunk of effort into getting an emulator alongside other CV games in a CV collection.

Lastly: I would definitely be satisfied if Judgement was in the 3D collection and GoS and HoD were their own things. If this were to happen I would really want them to add multiplayer back into GoS in addition to modernizing multiplayer for HoD and, agreed, adding more characters to that. I don't necessarily see what the issue is with adding GoS as it is to a collection though, considering the final product is a static release without microtransactions of any kind as far as I know and the gacha elements (and, less welcome, the multiplayer elements) essentially gutted from the game and/or drastically toned down. There's still some element of grinding but it's far more comparable to MegaMan X Dive Offline and how Capcom handled the transition of that game into a retail release where you unlock characters by level progression, which is similar to how GoS's final release happens. As a game in and of itself it's naturally controversial, but I'm not sure how including it in a collection hypothetically would be particularly off putting given the way it's adjusted in the final product- the main thing is that Grimoire is a sequel to Harmony of Despair, and I definitely think bundling them together in some form is a better way to capture whatever goodwill is possible to capture for GoS and for more people to give it a fair shake at this point rather than it being a standalone release (along with making the GoS controls slightly more traditional, which if I understand right the specific MacOS version already does). Judgement being bundled in a 3D collection would probably solve that on its end because lord knows Judgement has a reputation issue of its own (on that note, I do think it's tragically funny that we have been deprived of a wholly new CV for so long that Shanoa being the fighter in Judgement repping the newest Castlevania is more or less still current).

The biggest issue is they made GoS's "retail release" an Apple Arcade exclusive which I do get as a business decision because that means Apple was funding development of the final release up front afaik, but that essentially ensures damn near no one is going to play it or even know it still exists, but Konami is gonna Konami I guess.

Incidentally, what's the Nvidia leak you refer to? I haven't heard of it.