You won't find my skaven teams in the COL or on other official leagues, as I don't tend to play there.
But I've just won a 1-minute per turn tournament with skaven and have played skaven for some seasons in the Twitch BloodBowl League from Knights Division up to Emperors.
First, I'd like to say that I fully agree with your ROgre sentiment. Yeah, he CAN put on some hurt, threatens to crowdsurf even - but most of the times just adds an element of burning up RR or straight causing turnovers.
I'd say, that he just isn't useful as a roadblock (as you describe). AV8 for a big guy is just too low. Most of the times he will get hit by other big guys, setting his AV to 7 by default. Not good as a punching bag.
A linerat will do just as fine a job of taking a hit and you can reliably use a RR on it, should the need arise.
I always go for 4 Gutters, 2 Storm Vermin and a thrower, maybe two if you can't handle the team with just one. Rest is linerats, up to thirteen players. One more than I'd like to have TV-wise, but skaven are fragile and the extra won't hurt too much at 50k.
Developing Gutters and Storm Vermin is most important, the linerats can go with kick, dirty player, block or a lucky guard. Foremost they are the cannonfodder to protect your Gutters. Those are your play-makers, trust me.
If you want advice on how to develop the positionals try to find my teams (don't know if you can in BB2 from the top of my head) Ratz of Fame or Angry B34v3rs. Ingame coachname is Wolfskin.
Or just ask in here.