I think the addition of Worf transformed his character AND helped DS9. I agree that DS9 did not need Worf to survive, but he brought a different dynamic to the show and his character over the years became a far richer one.
I love Martok, but I think one of the reasons his character is so beloved by DS9 fans is the interplay and dialog between Worf and Martok. I think if it was simply Sisko and Martok, Martok would have wound up a different type of character. Similar but different.
I'd take that bet. I would love a vote by DS9 fans to see whether they loved the Martork-Worf moments over the Martok-Sisko interaction. I'm definitely a bigger fan of the latter. Then again I'm also more of a fan of the Sisko-Dax relationship (platonic as it was) than the Worf-Dax relationship too.
I'd be curious about this too. I'd love to see someone start a poll thread on it.
Me? Give me Martok any day of the week over Worf.
Martok was the much more interesting character precisely because he was ALL Klingon, had not been raised on a Federation planet, and was not in Starfleet at all, let alone being under Sisko's direct command.
Sisko had to co-operate and work with Martok to win the war despite the fact that they were very different people from very different cultures...and neither had the right to command the other.
I thought the Sisko-Martok alliance was one of the most interesting aspects of the Dominion War, actually. I wish they'd had more time to deal with the topic...but even with the time they had, it was very interesting to watch.
One of my favorite scenes from WYLB is the one where they finally have that opportunity to drink that blood wine standing on Cardassia Prime...and Sisko and Ross pour theirs out on the ground rather than drink to the utter destruction of Cardassia that is lying all around them.
Martok doesn't get it at all...but you could see him just shrug it off and think to himself "Those crazy humans!" and then he drinks alone.
A piece of utter brilliance!