Allow for the creation of particles based on a (non-contiguous) range of chapters, in addition to the present option of defining them by timecode ranges. Let's say I'm watching a TV series episode with six chapters: an introduction, opening theme, part 1, part 2, ending theme, and next episode preview. In this case, I would only be interested in chapters 1, 3, and 4.
Allow particles to be edited once created. Could be useful in case one wishes to duplicate a given particle to make minor changes.
Subordinate stack items appear unstacked every time MC is restarted. Not only that, but entering the context menu for stacks after discovering this shows the "stack" option greyed out and the "unstack" option active, indicating that MC still erroneously thinks they are stacked.
Allow for pre-selection (forcing?) of DVD/IFO/VOB subtitle tracks prior to playback. Unlike how it is when dealing with BDMV's and pretty much every notable container format, MC is currently incapable of "remembering" the last selected streams when dealing with DVD's or DVD's ripped in folder structure after playback has been stopped. Perhaps this can be done via a sidecar?