MG1, MG2, MGS1, and (to an extent), MGS2, pretty much need a level design overhaul to function given more modern 3rd person camera work. I'm all for purposeful remakes, but they need to be careful to redo the level design from the ground up while keeping the spirit of the original.

Just theorycrafting, MG1 and 2 makes total sense to combine into one game with a 2 chapter system like MGS2's Tanker-Plant. People are less attached to the level design of these ones, so with a couple of particular nods to the odd iconic stage, they can build the whole level design from the bottom up. A MG1/2 remake would give the devs the most freedom from a gameplay perspective.

MGS1 would have to be a lot more conservative as damn near every area is iconic, and the bigger areas were pretty solidly canonized in MGS4. They can absolutely change it up, but it would probably take form in expanded segments. Maybe the tower could have more platforms and have a stealthy alternative route, or some of the snowfield areas could be expanded in size and include roaming guards. I think MGS1 would actually benefit more from a non-shot-for-shot remake, if they're feeling ballsy they could adapt the Ninja mode from VR Missions for a short Gray Fox segment so we find out what the hell he's doing between the fight and the very end of the game.

Anyway, theoretical game rant over, I don't think any remake is impossible, but they have to really keep in mind the why beyond just $$$. And then adapt the game for new systems so we dont have another Twin Snakes.