I think it would have had more drama and emotional depth if Jack had had to sacrifice his grandson because he knew it was the only way to save the Earth, rather than having to be "pushed" there by the third team death in 5 episodes. (Someone has pointed out that it would have been more wrenching if Ianto was faced with a Sophie's choice between his niece and nephew, which I also agree with. If the point was to be dramatic, why not break new ground instead of repeat Tosh and Owen's deathscenes?)

Also, the more I look at Ianto's death scene, the less I understand the motivations of taking an unprotected man into a room with the intention of shooting the hell out of glass holding back poisonous gas. Had they been successful or unsuccessful, either way, Ianto would have died, which strikes me as being a poor plan, on both their and the writer's part. You'd think at some point in the proceedings Ianto would ask "what happens if we do shoot it up?" (Y'know, I think I just found my story for ninja_teaboy.)