I haven't watched this/last week's DH yet, but like you, since about episode 2 I've been getting tired of the "mission of the week" and impatient for whatever the real story is going to be. Although I suppose that the different missions that Echo has been on so far are showing us that each imprint leaves something behind - like a black marker on a whiteboard (sorry, teaching analogy!) you can clean off what you've written but there's always a black smudge left at the end of it!

I'm not wild about Eliza Dushku either :(