A lot of heavyweight bloggers and aggregators used Reader in their toolchains - it was very good at surfacing trending content. I don't think the effect on the blogging ecosystem was small.
I could believe they were clearing a path for G+ and Discover on Android.
What's frustrating is that Reader would have been complementary to Google+. It could have served as a huge funnel by which users could discover content to share on Google+. That's how I used to use Reader (though at the time I found content that I shared other places, such as Facebook, Digg, or Reddit).
I could believe they were clearing a path for G+ and Discover on Android.