To a world that hasn't thought all that often about Gilad Shalit in recent years, one of the most shocking things about the pictures of his release yesterday was his youth. He had been a soldier for nearly a year when he was kidnapped. He has been kept in captivity for more than five years, an experience that would surely carve on to anyone's face more years than have passed. And he looks like a child.

He looks, in fact, almost exactly as he does in the haunting archive photos that found their way back on to front pages last week, when the deal to free him was announced. To see Shalit, 25, greeted by Benjamin Netanyahu, Israel's bear-like Prime Minister, was curiously moving, whatever one makes of the Likud man's politics: the father of the nation greeting back the lost son it took so much to bring home. Israel has brought 16 soldiers back this way over the years, at the cost of 13,509 prisoners of its own. The transaction never gets any less extraordinary. If Shalit looks the same, the country and the crisis he returns to do not. The complexities of a grim situation have been further complicated by his release; whether for better or worse isn't yet clear, but it is hard to be optimistic.

There is certainly something to be said for the idea that any day which sees an agreement between Israel and Hamas put into place is a good one, and the spectacle of the young man's return – to say nothing of the rejoicing families of the 1,000 Palestinian prisoners also released – was inescapably powerful. And yet. It was just as inescapably unsettling to see Shalit immediately stuffed back into his Israeli Defence Force uniform for the photo-opportunity, and to see Palestinian youths throwing stones, and being teargassed in return, at a West Bank checkpoint. The cold, hard calculation at the end of this, when the surrogate joys of reunion have faded, is that Hamas is stronger, and Fatah weaker; it is surely not a coincidence that the deal came so soon after the Palestinian President, Mahmoud Abbas, strengthened his hand internally with the play for statehood at the UN. Now Hamas can paint that effort as mere grandstanding, in contrast to its own concrete achievement – the release of these prisoners, after all, is not subject to an American veto.

Perhaps it will be the beginning of a new spirit of conciliation on both sides. But in Gaza City yesterday our reporter Catrina Stewart heard a crowd chant: "We want another Shalit." And if another too-young man is indeed taken hostage, what will happen then?