I am having the same problem. I have upgraded from 7.5 where I found the campaign manager to be a lot more user friendly. For instance, after a campaign has been sent you could click the subscriber tab and it would give you the contact, the email address and would let you know item by item if it was successfull or failed, and from there you could delete the successfull ones and resend the failed ones over and over till every one was successful. There is no colum in 8 that tells you failed or complete. Other than the log notes, I cant figure out which emails where succesfull. From the log notes it would then be a manual process, which is not what I signed up for in this program.
If you get an answer to your question, I would love to hear about it.