Re: Well, let's face it- the acting on the show isn't great in general
Roseanne was considered "groundbreaking" for one not-so-great reason (the level of vulgarity) and a second reason that doesn't even have anything to do with actually being "groundbreaking," which was that it was a show about fat unattractive down-on-their-luck Midwesterners in an era of one attractive upper-class/yuppie NYC/LA sitcom after another. But that wasn't actually being groundbreaking. That just means it was a throwback to a mere decade earlier, shows about poorer folks like All In The Family (which easily blows Roseanne away) and Good Times and Maude and things like that. Shows that happily courted controversy. This was at the tail end of the Reagan era that Roseanne showed up, so like Blue Velvet its "controversial" elements have aged badly as, uh, Western civilization got more and more open about being vulgar, or something. I'd much rather watch Married...With Children, which, while a spectacularly tacky show, is more bearable because it had no pretension whatsoever of being taken seriously.
When I say "villains" I'm not really talking about recurring characters like Mull. I'm talking about crappy, poorly-acted one-shot characters like Jackie's abusive boyfriend who got pounded by Dan, or any of Roseanne's crappy bosses like the one from the fried chicken episode that Joss Whedon wrote, or the guy who was Little John in Robin Hood: Men in Tights and confronts Dan in the bar, or David and Mark's mother. There are more examples too and it was always the same thing to pander to the audience: the Conners may be vulgar turds but here's somebody REALLY bad!
I know Roseanne's acting from the earlier seasons has been taken to task, we all know Metcalf and Goodman were better. The kids were horrible though too. Not just horrible people--I genuinely don't think they were good actors, either. Sara Gilbert is on a talk show now for God's sake.