Also, the Icons used (called Image in the Customize View dialog) impact sort order in the Tree. Each icon will sort alphabetically in its own group (and the icons themselves have a pre-defined sort order). This, combined with the Auto, Top, and Bottom sections, allows you to get lots of different orders.
I agree that some way to custom sort them via drag-drop would be cool. I’m not sure why that’s never been offered. I think it might be challenging from a UI perspective a bit (you’d probably need to have some kind of “jiggle mode” to avoid accidental sorting during use), but the limitation may also be technical due to the data type of the Views underneath, or perhaps performance. Dunno.
Either way, play around with the icons. Having different icons makes the different Views easier to visually identify anyway.