I think both were too long. Miracle day should have been five or four episodes, and CoE should have been three.
Besides, CoE didn't really have that warm feel the first two did. In 1 & 2, we had "the gang". Jack, Gwen, Owen, Tosh, and Yanto. In CoE, I didn't feel there were enough cast members to really make it work.
At least in Miracle Day, I feel it eliminated that problem by adding in new cast members, something that I feel CoE really should have attempted instead of bloody killing off another
I want them to do a fifth series desperately, but only because I love the first two so much.