Achieving good speeds on open areas

[Mexicouger]

Well With sufficient knowledge, you can jump that wall and keep going with Quake, right?

[Spike]

needs different map preprocessing, it stops it from being quake-compatible.
but then so does using a q3bsp, so whatever.
blurgh, what am I saying... I'm too lazy to write the tools.

[mh]

There's plenty of headroom in a traditional GLQuake style renderer for improvement, yes (up to 8x under heavy load is the best I've got so far, but that's with mostly MDLs; 2x to 4x is more realistic with brush surfaces), but there is only so far you can go and the formats are still not optimal for what the OP wants.