I was entirely on the same page with you about Pierce for Barnes and I really thought we should have done everything we could at the deadline to try and convince Golden State they needed to make a move to go deep in the playoffs.
That being said, with the way the Warriors have played thus far in addition to Barnes seriously stepping up his numbers compared to his regular season average, I think this dream has finally died. No way they move Barnes with the way he is playing on a rookie deal.
I still think Golden State could be a landing spot for Pierce but it would probably be more of a package like:
Boston gets:
Ezeli, Biedrins (expiring), Jefferson (expiring) and 2014 first
Warriors get:
Pierce and Terry
Golden State brings in PP and his expiring deal to mentor Barnes and provide veteran leadership in exchange for their big expiring contracts, Ezeli who has upside and their 2014 first (which is probably going to be late in the round).