1. Entity key-value listings as per AD in TB.
2. Entity state stuff as per AD.
3. Ersgan quality subtle and faithful improved definitely textures.
4. High quality faithful monster replacements as per the AD shambler.
5. Slightly nicer flame models but retaining a similar style, not some weird fuzzy bloomy shit.
6. Coloured fog per area without hacks.
7. Gamma control that slightly increases contrast and saturation along with brightness to compensate for the washed out high gamma issue.
8. Subtly improved water with gentle surface movement and refined texture.
9. Ability to blend textures into each other across a join (wishful thinking?).
10. There might be more, if in doubt think "subtly improved quality and quake-faithful" .

I have no idea whether these are engine, editor, or game related or whatever. I like Quake tho. 

Lol wtf a monster model is not an engine.

Fog volumes and texture blending are manipulated by shaders in Q3. It would seem more appropriate to port Q1 monsters to Q3 for some kind of single player Q3 mod.

Q3 mapping with terrain and texture blending (actually from Q3:TA), where the artist essentially has to code the shader and specify the textures, is significantly more demanding than Q1 mapping.

Which is why modern engines has node system so artists can design shaders themselves. I'd like to see a node based shader system in Q1... ... ...
But I'm gonna wait for hell to freeze over first cause none of this shit is ever going to happen. 

I have no idea whether these are engine, editor, or game related or whatever.

Emphasis on the "whatever". Also this thread is derived from a "how to attract coders to the Quake scene" thread so I presume general coding might be considered. 

All of the above could be done. Some engines already support different model formats, so it's a matter of content more than engines.

I think there's a lot that can be done with water and fog that doesn't break compatibility and art doesn't violate the esthetics.

Not sure about blending textures though. But a low res masking with multitexturing could be an interesting addition. 

@Serious anon guy
Since you can run Quake3 in FTE, maybe this engine already suports shaders, fog volumes, texture blending and terrains... but i never played Q3 with FTE, so i really don't know... 

There's an argument for saying that 99% of the features that will ever be requested here can just be replaced by the sentence "turn the quake engine into the quake 3 engine", and that's not actually too far off the truth.

Darkplaces and FTE both support Quake 3 bsp and md3. Wraith: Age of Onions is built on Darkplaces to take full advantage of this.

The 2 feature requests currently in the github thing (lit water support and md3 model support) are again Q3 things and you can use them in DP for example.

I think I personally look at the quake engine and see something which is obviously ugly and bad (fullbright water and horrible jelly models preventing you from making big boss monsters that don't look like shit) and then say "would be great if we could fix this in quake 1".

For me I feel like I don't quite want the cross the fine line that has "fix something obviously sucky about quake" on one side, and "make everything like quake 3" on the other. 

Quake's animated textures SUCK. Making a waterfall using animated wad textures looks like crap because the framerate is so low. Also, switching the texture on a brush model is extremely limited - you can currently only toggle between two texture states.

Now, I could put in a request that says "full quake3 style shader support lolol", but really I just want to fix the obvious suckitude with those two existing quake features.

I'll need to have more of a think about it, but I'll probably submit some suggestions along the lines of making quake's existing animated texture support less shit.