MS Word's 'outline view" is a little-known feature that allows this: you can expand/collapse sections of the document (based on the headers, or anything with "outline level" paragraph formatting) and click/drag the folded sections to reorder them.
It also works with paragraphs, it has an option to show only the first line of each paragraph to facilitate the same click/drag reordering.
Tip for long documents: If you have an outliner that works, and can fold text, it is fairly trivial to reorder your work, and arrange it like paper furniture in a model of a room, until you get it just right.
For normal stuff, I do this on a smaller scale all the time, right here in the "add comment" box at HN... type up ideas in a stream of conscious fashion, review what I've written, and then click the button.
Then I review it again... and sometimes go back and edit for clarity.
You can do all that in any text input field of sufficient size... Capture | Organize | Synthesize
There are no new tools required, just some skills/habits to learn.