@Charibdis08
Full re-install of the launcher and game client doesn't appear to have had any beneficial effect.
The launcher is still displaying the graphical issue with the background.
The game itself takes ~5-10 minutes from selecting a character to loading into the game. Monitoring details for running tasks I see the game client go to "Not Responding" but still consuming memory, typically going up to 1.5GB. I've noticed a few occasions where the memory went from 1.5GB to 200MB and then slowly climb back up. I considered potential memory issues, however, I've experienced no issues with other more demanding titles in an attempt to determine potential hardware issues.
Once loaded there is sometimes a delay between seeing the area and the interface finally loading and the game being playable. There are "stutters" when looking around regardless of what the graphics are set to (Low or Ultra, 1024x768 up to 2560x1440, result in the same experience).
Right now am at a loss what else to attempt.