If 20 users pay for 15 Mb service, and they all watch Netflix, is it Netflix's fault the infrastructure can't handle 300 Mb of traffic? So is Netflix the major bandwidth hog, or is it just those users?

In your unlimited data from AT&T example, you are implying that Netflix is the consumer, but they are not. If I use more than 10Gb of data does AT&T charge Reddit because they were the reason I went over? No they charge me, the consumer they have a contract with.

It is extremely dangerous to let broadband companies choose what data provider has to pay more, because it allows them (proven shady and monopolistic organizations) to control what information is visible and what is not. On the other hand, if they charge consumers more for using more during peak hours, they would have no control over what is visible but still get paid extra when people are hogging the bandwidth.

the government wants broadband classified under Title II, but wouldn't that eventually mean that they could more easily wiretap and censor our communications?

There is absolutely no connection between those two things. Title 2 does not turn over utilities to the government, it does not grant special access for the government, and the FCC has nothing to do with the NSA. All title 2 does is regulate the business practices of the companies involved. It forces them to act in the best interest of the community, and it provides consequences if they discriminate in some way. Not to mention it is already extremely easy for them gather your data, they don't need any reclassification to help them. They just use secret courts to create secret subpoenas that legally require a company to hand over your information in secret.

Also, isn't the Bureau of Consumer protection relatively new? They don't really have a track record yet, whereas the FCC has already fought against big monopolies in the past.