After browsing the website, it looks like GC is nearly dead ?
It's a really pitty because from the small tests I did I find the terrain quality very outstanding ... Erosion looks soo real, and just the basic 'noise' do a fantastic job.
The dream would be world machine nodal system with GC filter quality and iso subdivision system ... but I can live with the actual layered system too.
For now my biggest concern is the limited terrain size (looks like a 64bits is needed to go over the 4096 limit ... supposed to be released in 2012).
And of couse filters should be multithreaded, 4096 terrain erosion can take 1 hour to generate :S
Not sure if Planetside could do anything about this, GC is a really good Terragen's friend, something has to be done to save him