Funny thing is, I myself won't be using the flare mod, I just thought it'd be a good idea after seeing people complain about the lack of lighting, and figured it was more creative and limiting, and also a cooler effect than just duct taping a flashlight onto the gun.
I plan on playing through Doom 3 untouched, as it was meant to be by iD, but I just wanted to see if I could do this, and it turned out pretty well
For a future release I hope to have it so that you can have both grenades AND flares, and when you pick up grenades it adds the same amount of flares to your inventory.