S2 is certainly about Downton, just the war's impact on it; the war is a central plot line, and was inevitable given the timeline of the show. In many ways it details a struggle for the future and legacy of Downton, just as S1 did. In S1 we see the noble family as well as their servants rebelling against the notion that a commoner outsider will one day rule over them. And while they come to grips with it throughout the season, in S2 we see the struggle magnified as Matthew's mother asserts her power and influence. All while each of the Crowley daughters goes through character development that moves them further from the protective wings of their family/house. I thought all that was compelling.
The problem with S2 was the increase in melodrama and subplots. Outside of Bates there aren't many demanding (or compelling) subplots in S1. S2 has a host of stories that don't seem to be relevant, and often feel ridiculously soap opera-esque. That being said, I really enjoyed S2 for what it was, and was quite emotionally invested.
The story was always going to expand, I just hope S3 does things smarter.
