When you create a party with less than four members, you still get a black, translucent box in the party display in place of missing members. Maybe it's intentional (for clarity) but I find it very distracting and kind of ugly...
Would it be possible to show the placeholders only when dragging members around, or to hide them completely along with the rest of the frame? Running a sub-optimal party like this seems like a "veteran" choice and shouldn't negatively impact the accessibility of the game at all, if that's your concern.
It would improve the look of 1-3 member parties a lot, methinks.