Doom 3 was already reasonably non-linear...at least by modern standards.
And that's the problem with enhancements. You just can't enhance Doom into modern gaming standards. It wouldn't work. Sorry if I didn't made the comparison clear, but what I mean is: Doom 4 will be as much different from Classic Doom than Classic Doom was different from Wolfenstein. Yes, it will be this much different. It will look like a completely different franchise.
I will give you an example: the level design.
Doom's originally intended experience heavily relied on its non-linear and abstract level design. This can't work on modern times. Of course, you can make the later city levels (when the world is seeming to be corrupted by hell) and actual hell levels (if there will ever be hell levels) pretty abstract and give some oldschool level design fell, but at the beginning of the game, everything will look like any other modern game, your standard modern game city level design will be obligatory. But this still is not a big issue if compared to level non-linearity. The modern players were born in an era of linear level design. Looking at Metacritic's user comments on Rise of the Triad reboot will give you an idea of what modern players would think of a modern game with 32 levels that requires you to pass thru the same place multiple times to find 3 keys to open locked doors in a sequence. Making a rail shooter like Call of Duty isn't the solution either. In my opinion, I think there should be a mix of level design. You have one linear level when you are running in the streets of a large ruined cities from hordes of demons and exploding everything Michael Bay style, and on other level, you are stuck in an abandoned factory, solving puzzles to progress to new rooms (I picture some puzzles that usually doesnt requires keys, but something that would fit the role of a key. For examplle, going from A to B to find a locked unpowered door, then having to go to C and find a power generator but it lacks the fuel, then you go to D and get some gas, while getting back to C, new enemies have appeared, walls have broken, and the general layout changed a bit, then you power up the generator, unlock the door, and go back to B and fight more monsters that showed up, then proceed to E (area behind the locked door) where you face a final showdown before the level exit). This would add non-linearity to some levels, and make both parties happy, add to variation and prevent the campaign from becoming boring and keeping the players on their toes, always expecting something different from the next level. But seems like the problem is a bit more complicated than this.
And of course, this is only the tip of the iceberg, but I just don't want to write another wall of text right now.
There is another problem with nonlinearity though. Back in the day, a room was made with two or three textures and maybe some clutter and was considered realistic. However, you can't just increase the texture resolution and poly count and still call it realistic and not looking jarring and weird. When you increase the quality of any asset, each other asset has to be the same quality. I am not an artist but I've noticed this and is something I call "pixel ratio" meaning things the number of polygons and texture variety a room should be made of should be directly proportional to the number of pixels textures have. I'm not sure if I've explained myself clearly but in essence when you make better textures for instance, you have to improve everything else too.
Now this fine and dandy but adds a problem. Because of all the clutter and extra stuff that is needed, it is harder to make landmarks. It is no longer enough to give a room a weird shape to make it look stand out. And the fact that it is realistic, makes it harder to give rooms weird shapes without them looking weird. Therefore making landmarks would be harder which is why it could be really easy to get lost. In Doom maps I rarely get lost but I have recently played Metro: Last Light, a linear game with just a few secrets and nonlinearity and I found myself lost during the game and the actual layout of the level is not very complex.
The way you described how nonlinearity could work reminds me a LOT of how Machinegames said the levels would be in Wolfenstein: The New Order. Basically some levels will be cinematic and some will be open for exploration. There was this really cool and classic secret in one of the trailers. You were in a room with a big painting and besides the painting there were 2 statues. If you used one if the statues, the player would turn its sword sideways and the painting would open, leading the way to a secret.
Last edited by DooM_RO on 01-16-14 at 08:18