Leave the OS on the internal and use the external ssd for media.
I'm not sure that will speed things up. I'm so disappointed! Several people with Apple told me this would work. Darn it. I guess I can try that.
On PC with Windows, yes you can run the OS and programs from the external drive provided the connection to that drive is recognizable as a bootable device by the bios which most bus connections are. All Adobe really cares about is what drive is listed as the system drive and where the user profile is located. As long as the drive letter is C then that alleviates most of those concerns on the PC. OSX is different since it doesn't mount volumes with a letter identity. The Boot options should not be an issue since the EFI should support any storage device bus option available on the Mac. The issue though may be the volume label in OSX and where the User folder is located. As long as they are in the same directory structure for OSX it should work. The key though is making sure the drive volume is mounted with the normal OS system identity for OSX which should eliminate unforeseen issues with Adobe's installer and user directories not working correctly because the programming did not leave these identity scan options open. You will have to try it though since Adobe wont support it based on that response. I will say the better way to do this is do a fresh install of OSX on the current system drive or replace it and then run a fresh install and use externals as media drives. USB3 for example has higher latency than the internal sata ports which would effect OS drives far more than data drives. Thunderbolt would have the same latency as Sata for the most part.