Israel has released people with more blood on their hands. He's not an Israeli citizen, but a diplomatic chess piece. He needs to be released before Abbas leaves the stage.
It is not just a matter of releasing him but of him being elected to replace Abbas at the soonest election following his release. He is not just another prisoners with blood, he organized bombings attacks during the intafada. He is not a just a soldiers, he was a "general" leading the war.
For now there can be no election till there is an agreement of unity between Abbas and Hamas.