What it all boils down to: Doom 3 was a different single player experience than people were used to, and different from what they were expecting. You either liked it or you didn't. There is no need to tie your own ego to a game that you did nothing to produce. If you don't like it, quit hating on it. ("Hating" is not the same as criticizing or discussing what you do or don't like about it. "Hating" is when you bash it every chance you get or ridicule people who did like it.) If you thoroughly enjoyed it like I did, accept that other people are going to have a different opinion.
Personally, I really enjoyed Doom 3. There were a couple parts where I felt like I was just trudging through, but the fact is I feel like this in every FPS I play. In fact the much vaunted Half-Life was one of the games most guilty of this for me. When I did play Doom 3, I played it with my headphones on, preferably in the dark, with no distractions. I was consciously letting myself be scared, much like one would do when watching a scary movie or visiting a "haunted house" or whatever. It was necessary to maintain that mindset while playing to truly enjoy the game, in my opinion, because that's what the game was designed for. It wasn't designed as a game you pickup for five minutes, frag some zombies, then put down to come back later, or a game you could play while watching TV or running Winamp at max volume.
That being said, I think the multiplayer is just Q3 DM with no railgun, and that my FPS is too shitty for me to enjoy the MP (in fact it impeded on my enjoyment of SP, too, a few times, but not many). I don't think there will be a ton of mods for it due to its high network requirements for mp and the huge amount of artwork necessary just to make an original texture set or monster/player model. Let's face it, 90% of existing mods can't even get the low poly HL models up to HL standards, let alone Q3 or better games. I'm just hoping some nice single player maps come out because that's an area of modding that has really been hurting since the whole Q3/UT/CS "let's only make MP FPS games for the rest of our lives" thing started. And don't forget the SDK only came out like a week or two ago. Sure you can code an instagib mod in that amount of time but anything with any depth will take a lot more time to come out. Even longer if they need art assets.