While I'm usually supportive of free trade, I'm starting to be sceptical of some of the provisions of the TPP, so I suppose this is a good thing.
This is type of legislation is required for US involvement in pretty much any multilateral trade deal in the future, and its absence can make bilateral trade deals more difficult. I like the idea of more oversight by the Senate, but I'm not sure how it can be practical here. If the agreement isn't something the Senate can support in the end they can still vote it down.