Wow, it's actually reassuring to see someone not hating Rossiu. I'll admit at this point in the story he does seem to be the bad guy, but that's only because he's a very logical guy. He's always thought things through, even from the start, and I doubt that city would be nearly as organized and well kept if Rossiu had not been part of the original team. His personality may not fit in with everyone else, but that doesn't mean he's evil. From what I see his intentions are good. He's just willing to make sacrifices (although he clearly struggles with them) where as Simon refuses to back down. That's actually one of the more interesting scenes in the last episode is where Simon complements Rossiu on all he's done, despite their differences even he is willing to accept that Rossiu made a logical choice (although that may not be the right one).
But yeah, I think that Rossiu is easy to hate, but I really appreciate his character adding a new dimension to the story. I can understand all the hate, but I hope people come around to accept that he isn't a "bad guy". Despite all he's done, I'd say it's obvious that Simon and co. will still pull through.