Doom 3, in my opinion, is actually a rather mediocre game - it was in 2004 and remains even more so today. The game sported attractive visuals for the time, but suffered by uninspired level design (excessive darkness, same corridors over and over again), obnoxious game mechanics (necessity to swap between flashlight and weapon - so you were either defenseless or blind), and lame story.
The BFG edition allegedly tries to fix these problems, but when the lighting conditions are adjusted, the game's extremely low resolution textures become apparent, and compared to games like Dishonored or even Borderlands (for mindless shooting), Doom has little to offer.
The reason behind this rehash is obviously an attempt to milk the game for more revenues by releasing the game on consoles.