The system is working because its was never designed to allow popular 50% majorities to enact what they want.
Madison was pretty explicit about this.. Gerrymandering and protecting the landed is built into the system.
I'm not saying the house would be the same in 2010 if the dems won, it just would be gerrymandered another way with certain people being disenfranchised not others. There is no way to get rid of gerrymandering without abandoning geographically contiguous districts.
I don't think expanding the house does much, you'd have to pretty much double it to see any appreciable difference and even then what are we getting? A more responsive legislature? I doubt it. I think say half a million is a pretty good size for a country of 300,000 ,0000. But again look at state and local elections, it doesn't take much to capture the representatives.
My point is liberals if they want to talk about change should fundamentally rethink many things in the constitution rather than tinker with ultimately meaningless changes (adding more representatives, term limits, non-partisian district drawing). Changes such as senate reform, electoral reform (changing the staggering), finance reform on the constitutional level, etc.