But the thing is, the Democratic coalition is shifting toward being more, not less packed. The Obama 2008-Romney 2012 areas are all outer suburbs and rural areas. A lot of the urban areas went from 75% to 80%. The only really promising areas for additional house gains are Florida, the rural West and some suburban VA districts that probably weren't gerrymandered enough.
Then again, for all we know, we could be looking at Obama 2008-Romney 2012-Clinton 2016-type-districts--well, under the overzealous hypothesis that HRC will be the Dem nominee in 2016. Or at least someone with more of a "HRC 2008" base (i.e. more Blue Dog populist appeal than Obama)