Well first of all thanks for your comments, I really appreciate the input everyone gives.
The reason i was saying it doesn't seem up to my usual standard is because it usually takes me a lot longer to get a map up to a high quality. But don't get me wrong, I'm loving how this map has turned out, it just feels a little rushed.
Anyway, like I said before its a bit of an experiment outside of the usual bounds of HLDM. Like you Reno, I though the R's would be huge, considering you can see lots of the map at anytime, and the whole map is in one area. But I was pleasantly surprised to find that the R's were a lot lower than expected. The highest they get is 1500, but only when you noclip up into the air and can see the entire map at once. The highest it gets at any point on the map is 1200, which is a little bit high, but well worth the sacrifice for the spinning rubble vortex.
And, thanks for the suggestion Campaignjunkie, but the rubble already spins. It's all divided into six func rotates that spin the same way but at slightly varied speeds, making it look a lot less uniform than one would expect, considering each func rotate is constructed using the exact same brushes.
I was a bit worried about the lighting, but the nature of the map makes fixed/visible light sources a problem, they would also cause a significant jump in R's. The current effect at the moment gives the impression of lots of downlights shining from above, and it looks ok. Also the jump pads have some problems (see profile for description), but theres not much else I can do with them. I had thought about replacing them with teleporters, like you suggested KIIIA, but bounces suit it a bit better I think.