Simply net neutrality is your ISP ignoring the contents of your packets and simply routing them to their intended destination.
Repealing net neutrality would allow ISPs to more interesting traffic shaping based on the contents of the packets, e.g. allow unlimited data caps if the user pays for the ISP for unlimited netflix.
The pros for net neutrality are that the ISPs have historically done all of the practices that you mention. And actively practice them in countries like Portugal which have no net neutrality.
The con is that some sites are much heavier bandwidth than others, and do represent a much higher cost to the ISPs. For instance I've read that netflix takes more than 50% of North American bandwidth during peak hours. Repealing net neutrality would allow ISPs to have more flexible pricing models that in theory could allow the consumer cheaper broadband by choosing different traffic shaping options. In my opinion, this is unrealistic because ISPs are a natural monopoly in most places and thus the incentive is to skew pricing for what costs their routing infrastructure the least rather than be competitive with other ISPs.