[Badger]

I think the others have more interest in Hurley, Sawyer, Jack and Kate then they do getting Henry Gale back. The reason being the others could simply traded Walt for Henry if they really wanted him and were really going to give Walt back to Michael. Also I'm doubtful that Walt really has any supernatural powers. Everything mysterious about him can easily be explained by coincidence/Michael's delusion. The scene from last weeks episode makes me wonder if the others may even have him playing against his own father. Maybe the scene was just contrived to make it more dramatic and less realistic than the others would really allow if they wanted Michael to have no more information than he's alive.

It seems to me if the others wanted to keep Walt and get Henry back they could accomplish that by just capturing someone else.

I also share google boy's theory about the others not being the originators of the experiment, but rather just being caught up in it. We've already seen them capture and maybe assimilate people from flight 815.