Apparently, the sources "think" the release of the terrorist will somehow help negate Hamas, but I am at a complete loss as to how that is expected to work!
That's exactly what they think. They think the Palestinians love Barghouti and that he will defeat Hamas by popular support. It also means they think Abbas is dogmeat and they need another leader.
Trouble will stir and Abbas will call for new elections and Bargouti will come to the rescue as a populist winner of the new election.
You never know. He has been in Israeli prison now for many years. He could be a double agent by now. (just a little bit joking).
More seriously, it's clear Israel is serious about 'introvergence' and that in the absense of Israelis the Palestinians need some kind of serious leadership. The west have nothing in Abbas and no respect for Hamas so... big change.