First two words that popped into my mind when I read the title of this thread:

Richie Havens!

Whenever anyone speaks of "just strumming" in an apologetic or belittling manner, just think of him.

(Of course, not everyone has The Voice to go with it...)

The simplest minimal approach to guitar-as-percussion-instrument can be tremendously effective -- IF the player can bring a sense of conviction and a full-out commitment to the effort.