Although I like @Dale Emery's "metadiscourse". See
http://learningnerd.wordpress.com/2006/09/06/english-grammar-types-of-phrases/
for the names of common type of phrases.
If you spend a lot of time talking about what you're talking about or introducing and qualifying statements instead of just saying them, it makes them more complex and tends to be distracting or annoying if it doesn't actively contribute to understanding the rest of the sentence.
Phrases like this can be beneficial if you need to frame a concept in a particular context before stating it - instead of putting the context at the end of the sentence.
In fiction writing, prepositional phrases can be used to set the tone.
Prepositional phrases can be used to set tone in fiction writing.
The first way just sounds better to me.
The problem is that additional phrases like these make the reader save up their contents and then apply them to the rest of the sentence. It makes them think more. Sometimes it works and sometimes it doesn't.