In general, our data shows that most users don’t have any (or many) SBS or MPO files. So this issue only affects 3D enthusiasts. The change was made to be easier for the masses who are often confused about the difference between Lightfield and Stereo mode. Often when I show people and they switch between them, they can’t tell any difference, they just mention that they “can’t move as much” when in ST mode. Of course, this is dependent on content.
For full context, there was also another critical bug that was caused by having the view state saved per-content with the addition of the 2D to 3D video conversion. That would have taken much longer for us to fix, so we decided to make this change one version early so we could get this out to users faster and move on to the next one as I know everyone has been waiting for this release for quite some time. In fact, part of the reason we pushed hard to get it out faster was because you had pushed for it.
Your feedback has been heard, and a solution will come, but if you want to set your files into ST view mode, your two options are to revert to 3.2, or wait for 3.4.