Why does this sentence sound odd?

Maybe it sounds better to you because a pleasure to read parallels the structure of a breeze to write, while actually updated in real-time doesn't, so you subconsciously think of it as being separate from the former two. It feels a little awkward to me too, but including the are makes the sentence ungrammatical -- unless you move the and too:

Live blogs that are a breeze to write and a pleasure to read, and are actually updated in real-time.

I would say "live blogs that are a breeze to write, a pleasure to read, and actually updated in real-time," in the same way I would say "I have eaten, worked outside, and posted on a Q&A site all day."