Apparently there are some problems with the client_settings.ini files post patch that cause a huge drop in FPS. Multiplied across 4 accounts and the game was barely playable for me. This issue can be solved for most people by doing the following:

Navigate to your C:\Users\<youraccount>\AppData\Local\SWTOR folder and delete the DiskCacheStatic and DiskCacheStream files and then go into the settings folder there and delete all your client_settings.ini files. If you had ISBoxer virtualize them there will be one for each of your characters. You might have to run the Launcher Repair tool in your SWTOR folder to get the game to launch error free following this operation. Also, you will need to launch the game and reset your graphics settings to Windowed (Fullscreen) because when the launcher remakes those .ini files it will reset it to Fullscreen.

I went from super-laggy barely-playable to perfect 60FPS following this.

I work tonight and tomorrow night but I promise I will put up a manifesto this weekend. I've been pulling 16 hour days at work on top of a 3 month old baby at home