Without the reblog feature, people we follow do not always post what we want to see. There may be 1 out of 4 posts that I don't like but that doesn't mean I have to unfollow them. I don't share "ALL" the interests of the person I follow and, with the reblog feature, if he/she decides to reblog more of the things I am not interested with, it will surely flood my feed with more "unwanted items". Then, again, that doesn't mean I have to unfollow him/her.
I agree with @scaredycatguide about having a separate tab for the reblogged items.