Baserace has tons of tunnels and places below ground level to run in. I really liked playing baserace. But I think everything else lacks in the map. The visual, technical and feeling aspects are fairly bad imho. But nothing beats the adrenaline in the map. It is really hard to get that part correct.
In think Radar is well designed height wise and not flat at all. You can boost speed with strafejumping in well thought spots. Makes the map faster and more exciting.
What I am after is that big flat fields are slow to move on and easy to die on. My personal taste is that when you can boost speed with jumps it makes the most adrenaline filled and fun spots and maps. Eg goldrush downhill, fueldump slopes, radar main gate etc.
I also like that some major area is above/below regular ground level. Makes the fighting/hiding/sniping more interresting and adds variety. Think about railgun track switch, oasis garrisons and balconies or goldrush bank area.
To me flat maps are a bit boring and demonstrates weaker design in general. Makes me feel something is missing and map too simple. It’s like we would go back to 2d.
It’s not mountains in the middle of a field. Sometimes only a few meters can make a huge difference (think about how baserace would be if there was none of those trenches; nobody would know the map I think).
Also height is a good way to control the vis part. Field maps tend to have worse FPS, as everything and everyone will be drawn by the engine.
Now it is true, that I cannot really tell the height in the screenshot. It was just my first impression. So I wanted to speak out, because I personally hate when there is not much feedback when asked. I would rather talk about something like this early on than later on.