Jesse Sky is a world designer at BioWare Austin. In the most resent developers blog for SWTOR, he details what it takes to build a Flashpoint. He explains that it's not all about getting to the next boss fight: "Fighting through legions of enemies is part of what makes the cooperative gameplay feel heroic, but we find it helps if your enemies do more than just stand around waiting to be attacked." According to Sky, many players have run dungeons that have them wondering why they are there, with no sense of purpose. "We want you to feel like you are the heroes in a Star Wars action sequence, but we also want to give you opportunities to roleplay with your friends." Sky indicates again that SWTOR's emphasis is not only making a great game but also making a great story.
Be sure to read the whole developers blog on the official Star Wars: The Old Republic website.