If the Klingon homeworld at the time of "Heart Of Glory" truely is anything like that seen in most of TNG (and all of DS9), then the three renegades shouldn't have any complaint about the empire at all. Except for the treaty with the Federation, which they openly dislike.
The clear implication in the episode is that the renegades are social outcasts for their views about 'the glory days'. Worf's joining them in traditional death rituals and the like is depicted more along the lines of him humoring them, it wasn't supposed to be the way the Klingons behave 24/7!
An excellent opening post there, by the way. I enjoyed reading it immensely.