Man I really hate having to choose Right and Unlit every time I click on a Blueprint Viewport. I must do this hundreds of times a day, and it is really tiresome. I wish there was a way to change the default Perspective/Lit to something else in the project settings.
I was able to implement the requested change in https://github.com/EpicGames/UnrealEngine/pull/6231 (still to be reviewed by Epic). Cheers,