Hello Crocket,
Format>Line Spacing "Before paragraph" or "After paragraph" will free
up some area between the paragraphs and retain the space between lines
of a paragraph.
Hope that will make a hit of the one-liners.
You need to select all the paragraphs you want to apply the line spacing to.
Unlike tabs, where you get only one set that applies to the entire text box,
PPT lets you set line spacing on a per-paragraph basis.
Also, line spacing is ... well, either broken or weird-by-design when you apply
it to slide titles. Before/After paragraph adjustments don't work at all, but
Line Spacing does.