If Hamas is eager to negotiate it can only mean that Gilad's health is deteriorating and they know they have to make a move now. Gilad was very skinny last he was seen, and that was a while ago. I hate to think bad thoughts about Gilad, but generally speaking, a dead body is worth far less than a live soldier. And course allowing Gilad to die in their possession would give Israel the "political capital" to kill a few hundred and maybe even another 1,000 Gazans. So Hamas would be wise to make a move. Israel has the upper hand.
from the article: Carter: Hamas eager to renew talks for Shalit's release