2o0 block raidus
perfect size!
I'd just like to point out you said 200 block radius was too small for my map...
Now to the map. I'm sorry, but I'm really not a fan of it. it just looks uninteresting, and from the video we only see one half of the map right until the end, where a glimpse of the other side can be seen, and it looks completely bare. I can understand the idea of the 'infection' but it just doesn't look right. and there also appears to be random floating ice islands? I don't get it. Also some of the builds are of good quality, but the terraforming again appears to be kinda random, and in places oversmoothed.
I just feel that it's really random, and it doesn't fit.
Maybe try taking out the ice islands and then making the nether area look more natural, that would be a good place to start.
Cheers
benji_r