Should the use_single_view option perhaps be in the header of this panel, and get flipped to be a "use_multi_view" option?

I think it wouldn't be uncommon to work on a project where you will do stereo rendering but modeling, lighting and shading you don't care about that always. The use_single_view option is perfect for this but presenting it as a global multiview on/off button might be more obvious?

In that case the defaults could also change, with such a use_multi_view option of by default but left and right views enabled? As you might see from my other comments I really think it would make things much more friendly if there could be a single option that you turn on in existing scenes, and have it render, composite, display and save stereo renders.