Net neutrality is certainty for growing companies. AT&T née SBC, Verizon, Comcast, Time Warner... these are not companies that need a lot of growth. They're already huge. The simple regulation was pretty straightforward.
Not having a neutral network, which actually means not having fair-market pricing and having censorship power over content producers and publishers in the hands of the incumbent network providers means much less certainty for smaller companies that may be trying to grow. Will your customers be able to see your video without paying extra to receive it compared to Comcast's own IP video streaming? Will AT&T disallow traffic from a website that publishes an article critical of AT&T from reaching AT&T customers? This whole "pay to upload and pay to download at the producer, then have the consumer pay to upload and download at their end, then tack on extra costs for the consumer to download the content from only some producers" is an unfair business tactic and a cause of uncertainty among those content producers.
Pai is trying to make things simpler for the biggest companies on the network and much more risky and unknown for absolutely everyone else, and calls that transparency.