Logging into the beta I noticed the client no longer triggers Auto-HDR and seems to have built-in HDR support. The graphics settings page also properly detects HDR monitor outputs. As an AW3225QF owner using Dolby Vision, Auto-HDR is very hit-or-miss and would love to see proper HDR support in WoW.
I also noted much better 4K scaling within the menus, which is a very welcome change.