Nice read. I'd like to get an answer, but maybe the issue is too technical...
The short version: it looks like instead of having all the models and textures on your hard drive, being rendered by your video card, at least some of them are exclusively on the servers, rendered at least in part by the servers, and then sent to your client.
There's a theory that the MASSIVE reduction in hard drive space used by the game (something like 17gb I think it was) in the last month before the game launched might be because the missing assets were put into this remote rendering system.
There are a few holes in this explanation thus far, but it could explain so much...
Keep in mind that 'remote rendering server' doesn't necessarily mean a server located at Bioware. In fact, it is highly unlikely that Bioware is rendering images in this manner. What may be happening is that the second swtor.exe process is the remote server itself. The game may be simply sending all render requests to the second process by way of 127.0.0.1, the localhost address.
On that note, next time I'm playing I'm going to toy with some packet inspection.
Entirely possible: that other thread indicates the second process is "swtor.exe @RemoteRendererServer.icb" I find it highly implausible myself that they'd render it on the server.
What they could be doing though, is storing the assets on the server, and using the second process to decrypt and/or render them, which could still introduce substantial performance hits.