Transparency is a good thing in many contexts. I don’t think it’s a good thing in the specific context of negotiations. The place to negotiate is behind closed doors. What should be transparent is the decision and its implementation. But I know many disagree.
I think it’s worth thinking about this in other contexts, though. Think about a family negotiation over whose house you spend the holidays at, or who goes to watch Billy’s soccer game on Saturday. At the end of the day, wouldn’t everyone be worse off if the whole extended clan had the right to watch the negotiation on C-SPAN? More to the point, wouldn’t knowledge that the proceedings were going to be seen by others bias the negotiation. If your husband says “you don’t even like your cousin John” then you more or less have to protest and insist that you do too like him and any proposal predicated on the idea that you don’t like him needs to be rejected.
And that’s how it would go in negotiations. I think people think that if there was more transparency, the dread special interests would have less hold over the process. But I suspect the real result would be the reverse. What happens when you reach a compromise is both sides agree to sell some folks out in pursuit of some bigger objective they care more about. But in a transparent process, nobody would be willing to even hypothetically entertain the idea of selling anybody out.