There are many many posts regarding the fact that Adobe Acrobat is not an editing application. Attempting to do so results in broken lines and text blocks, crazy word spacing, etc.
There is a need for such an editing application; oftentimes publishers are handed PDFs that they then have to manipulate to fit their needs, be it changing trim size, editing text, or reformatting for audio publishing. So it would be wonderful if Adobe came up with an application that can be used to edit existing PDFs, with generic word-processing features such as styles, layout options, spell check, and review.