So about that flashlight
For some reason it never occurred to me until years and years past that duct tape meant that Doomguy just has to tape his flashlight to his gun. I saw how popular the Duct Tape mod was back on Filefront but I guess I never downloaded it because I thought it sounded dumb and it wasn't even a cool map or mod?
Even then you would need multiple flashlights to tape on to each gun and those are among the rarest tools in the Mars base so the shoulder mounted flashlight makes a lot more sense but even then you would likely make yourself defenseless trying to push it on and off again unless you can do it with your mind or a flex of the correct muscles. I also don't see any duct tape on Mars.
Having to switch to your flashlight isn't lucrative in the least but I appreciate the skill required to juggle a gun and flashlight. When you see that monster you have to switch to your flashlight and make an estimated guess to where it is to fire and I think that's pretty cool. I like the flashlight. I don't really have an argument I just really appreciate the flashlight and the interaction with the pervasive darkness it grants you.
I've played Doom 3 a long time ago, but I really get what they were going for. The design choice was to make it more horror and less action. I remember that instead of switching to flashlight I rather shot in every dark corner and wasted a lot of ammo.
Some missions are even built around flashlight. For example the one where you are escorting the robot. He has flashlight and lights enemies.
There are also more design choices that support horror aspect of the game. You are slower. Computers in the game are real time if I remember correctly. That's also a neat little thing.
I haven't played Doom 3 in years but I didn't think the flashlight mechanic was anywhere near as bad as people made it out to be. There's a few situations where you need to juggle flashlight and gun to see anything, but at that point you should be relying on sound cues to gauge where enemies are. Doom 3 (and specifically how it played a lot with light and shadow) is a big influence on my own design projects.
I've been going through it again slowly, it does kinda hold up well. The models clearly show their age but the gameplay itself is quite fun. The flashlight is a huge contention amongst Doom 3'ers, one camp prefers the original as it was more tense, another prefers to BFG style since it allows for slightly more action and doesn't make it feel like a Silent Hill on Mars with guns.
Who knew such a tiny change would have been such a huge gameplay chism.