What got me and most of the players into Q3 as a kid was creating an FFA match filled with bots and seeing what at the time was unparalleled brutal action. I spent literally entire days playing on maps like DM17 and these space maps were players would jump to the stars and you could blow them up and see the gibs flying in the air everywhere playing with full on GFX.
The weapons, sounds (from the epic badass announcer to weapons etc), characters and generally the aesthetics felt brutal and simply perfect, as some sort of interestelar gladiator arena. Everything was spot on.

What im saying is: Real newbies need this kind of shit. You need the shock factor. Then hopefully they will start to see beyond this and appreciate the intricacies of fine tuned 1v1 gameplay. You got to make it feel solid and brutal. Particles everywhere. Even destructible enviorements. At least partially. All the walls and different textures can be blow up and the room would get filled with flying pieces of bricks, broken glass and blood. Of course you can't blow up walls, but partially, as an added GFX to enhance the experience. Max Payne did this in a nice way years ago. This could be exploited a lot with up to date technology and no one has done it the right way yet.
Remember the first Matrix movie, the scene in the bank? The particles must look like that, and you could watch the replay of the fight in slow motion and it would be awesome.

Also, you gotta add motion blur, the proper one, like in Crysis. It would really add dramatism and make it more brutal, during close fights specially. Like when a player gets shot in the feet with a rocket and he is propelled in the air rapidly, you see the blur on the model and it's awesome.

And of course all other kinds of industry standard eyecandy shyt.

I guess you are keeping the maps closed. something you can have fast tactics on and read the player movement, and not these shitty open areas in modern games (Shitmania). So this basically means you can push all these GFX further since the computer will not suffer as much due the maps being smaller.

Of course add all kind of options so you can turn all of this shit OFF and have your good old Quake r_picmip 5 for us experienced players (even if I still enjoy a nice FFA with full GFX from time to time myself)