I love Shattered. It's one of my favorite Voyager episodes of all. I like the retrospective juxtaposed with Janeway seeing it all for the first time.
And yea, Chakotay was way underdeveloped, even for a cast that was largely undeveloped unless your name was Seven or Janeway. It kinda worked for me cause I love Seven and Janeway, but it would been a better show had the rest of the cast been given more depth.