The Old Editor (Plato/WYSIWYG) is obsolete and problematic. However, the replacement, the Visual Editor (the new editor you're referring to) Has to group content in "blocks" - so ever line is wrapped in [p][/p] intentionally. This conforms to bbcode standards and is intended. If there are extra blank lines, when editing the article in the Visual Editor, simply ensure the lines are spaced as desired. Empty lines will still have a [p][/p]

In regards to the UUIDs for headers, this too is intentional, as the new Visual Editor needs to be able to identify individual headings for use with the table of contents functionality. These UUIDs are not used anywhere else and should not be visible anywhere unless the article is opened, as you have done here, in another editor that exposes the raw bbcode (Plato in Source Mode, Euclid/Advanced Editor).

If the display of the article (Presentation view) is not consistent with what the Visual Editor shows, we can definitely look further.

I may have misunderstood your report, but from first glance this appears to working as intended, save for the extra paragraph tags (unless double and triple spacing of lines is intended). Feel free to provide more information if I've misinterpreted what you were saying!