Re: List of essential episodes.
You should add Maquis episodes from TNG/DS9/VOY as well. Together they form a great arc of stories.
For the Maquis I'd just stick with DS9 and TNG episodes. VOY terribly mishandled them. Even though half of the VOY crew were Maquis, their introduction and most of their development happened on the other shows. Just my two cents.
Aim For The Stars...