Did DS9 have a counterpart of any kind to B5's Londo Mollari? I'm not sure that it did, although perhaps Quark comes the closest with his vacillations between right and wrong.
Quark very well could have become the heart of DS9, but for some reason, the writers never let him rise above a comic character.
Many of Jammer's Reviews
make this point better than i could:
There's a moment in "The Dogs of War" when Quark has had enough. He has watched as Ferengi society around him has become, in his view, a travesty. And he realizes he hasn't been immune from the changes over the years; he sees that he has gone "soft." He launches into a histrionic tirade that continues to build in amusement as Quark's disgust is unleashed. Then he yells: "The line has to be drawn here! This far, and no further!"
the problem, though, is that unlike the rich and textured culture of the Centauri, their proud yet tragic trajectory (which, of course, mirrors Londo's own character), with the ferengi:
Even though developments in Ferengi culture in the past have been so badly handled that they cross into offensiveness ("Profit in Lace" especially), I think I finally see a payoff here to all the changes made, never mind their previous implausibility. That payoff is simple: Ferengi society has changed ... and Quark hasn't.
And that's probably the difference between Star Trek - which, like root beer, is so sweet, and bubbly, and happy, whereas B5 is like scotch - complex, at times bitter, certainly not for everyone, but if you enjoy it, it packs a fucking massive punch.
The thing is, in B5, Centauri prime tried to change (Emperor Turhan was
a great man); Londo did not. But unlike Quark, Londo did something about it, and everyone payed the price. Especially Londo.