A. I agree, Carmack is somewhat of a programmer genius, IMO
Idtech 4 was just the wrong tech for the wrong time, I believe, people were more interested in large open areas, where as idtech4, mostly showcased as rather enclosed, at least until megatexture, I think that will change a little with idtech5 though, as its easy to see with Rage, that the new engine is going to be well suited to all kinds of scenery, and has things that Unreal Engine doesnt have(go back and watch the original Rage techdemo videos, where they show the level editor aswell).
B. Honestly, will a fully 3d engine, I see nothing holding them back from doing a free cam, tech wise, and I am not sure about the slowdown you mentioned, I cant recall experiencing such a slowdown myself in TQ, and yeah I cant think of any reason why itd slow down from zooming in, unless there is alot of particles flying around(I noticed in alot of games when the camera gets close to alot of particles things start to bog down a bit), that I can explain however, since whereever the particles are, they are drawing on top of the stuff behind it, so those pixels essentially are being "overdrawn"(ie, the GPU has to calculate it twice), its fine when the particles are small on the screen, since its only a few pixels that get overdrawn, however if you zoom in the particles cover more of the screen so more pixels are being written to the screen more then once, and if they cover your whole screen, 1 particle means every pixel is touched twice, 2 particles means they have to touch the pixels 3 times etc, and when you look at spell effects and the likes, you're usually talking about hundreds of particles, as to rotating the camera, that would be the same regardless.
C. I mean afterall it only draws whats on the screen anyway, so having the camera at a slightly different angle isnt going to change too much, the reason for the fixed camera has more to do with how things feel, in my opinion, the free camera works in NWN1/2 because it is a slower paced game, more often then not I found myself pausing and issuing individual commands to each character in my party, having a fixed camera would limit your view of the scene, since you really need to take everything in.
Diablo however is pure hack and slash, its 1 vs many, even if you get a mercenary or pets, you never control them directly, they usually do their own thing, and attack anything nearby, so having a free cam isnt as important to gameplay in this case, itll only cause gameplay to break into a slower pace.
Diablo uses pure mouse movement, theres no keyboard movement, and generally you are holding down the mouse button while running around, jaming hotkeys, clicking on enemies, with no auto attack also means you cant let go of the button to hold the right mouse button and do a quick camera movement(plus its usually used as a secondary ability hotkey).
Thats my reasoning for it all anyway, take it how you like
D. Actually, I am working on the Quake 1 engine, itll be a complete standalone project, I implemented HL1 BSP(almost identical to Q1 BSP) today in order to learn the structure better, I havent gotten the lightmaps rendering properly yet, but I am not sure if I will bother, since I will be stripping out both Q1 and the HL1 support and adding Q3 BSP support, then I plan to expand the format from there.
I will take a look at those mods though, I mean thats where I started out

Q1 modding and HL1 modding(actually learnt C++ from working on the HL1 SDK....not the best way to learn :P )
E. Yeah thats pretty much the only reason I am doing it, I dont have much interest in the chip8 itself, and while I am probably at a level that the chip8 is too simple of a start, it does actually give a great foundation for future emulation projects(which will give me better understanding of the more complex hardware in PCs).
F. Thats actually something I didnt think of, more enemies would be a great thing for Doom 4, and makes sense with the lower FPS target, though it does conflict with the "looking 3x as good" statement, though no doubt it WILL look better, having more enemies will limit how much they can push the graphics, but if they did it that way, I am sure itll be a better game
G. Yeah, while ive heard people sad bad things about its graphics and the like, its not a bad game, and I actually reinstalled it this week since I had a cousin over who loves the SOF series, but I couldnt find my original SOF1 disc, so I installed this instead
H. I cant say I disagree, I mean I did spend more time playing Doom 3 then some other games(like SOF: Payback above), and even imported the textures and normalmaps into my super old Quake1 engine(mostly riding on other peoples code, there is some talented coders who worked on Quake1 engine projects), not even sure if I have my old source code, would be interested in taking a look at it again...great, now im gonna have to hunt for it just to quench my curosity :P
Doom 3 itself though, was definently much slower paced then other shooters, especially at the time, borrowing som
e elements from SS2(audio logs etc), and thinking back now, they did an awesome job of keypads/computer interaction, turning your crosshair into a cursor when looking at the screens.I also remember a video I made, which I am gonna hunt for now aswell :P