This is on our roadmap but we don’t have a specific timeline to share at this point. We’ll update this when we have more details!Ugo Marsolais commented
It's beyond me why you would implement a white theme WITHOUT still providing the option of keeping the dark theme if you wish. I mean, dark theme is all the rage now, heck, even Apple is going dark for the iPhone. Power BI is doing exactly the reverse. I cannot understand how Product Owner/Manager sometimes make decisions...