I agree with the fact that CTR has nothing to do with measuring success of the content network. That is 100% correct. Additionally, content network CTR does not count against your quality score for the search network. Regarding the content network being a waste of money for 95% of sites, where do you get a number like that? I have utilized the content network for many many clients. Some of them even convert better on the content network, especially in hyper-competitive verticals where keyword based bids are out of line. With that said, I usually start with the search network only, and then 'explore' from there as necessary.
I mostly use exact and sometimes phrase match because it helps me get a higher CTR and i spend less money on irrelevant clicks. Instead of relying on Google to find alternative keywords through broad match i prefer to take control myself by a thorough keyword research. I launched one campaign yesterday focusing on the "long tail" with about 400 keyword phrases (including ~100 misspelled combinations for only one single "parent" keyword). During the keyword research i found a about 80 negative keywords i blocked out out. This really helps the CTR and prevent you from getting irrelevant clicks. Creating long keyword lists is not difficult with the right tools. It took me about an hour to generate the lists and import it to Adwords.