Only a small section of the fandom thinks Ianto is going to die, and have been thinking so since Season One. Ignore them. He is a brilliant character who JB admits keeps Jack "human" and Ianto is slowly becoming a key member of the team, and the most popular character after Jack. It's that element that I think threatens people for some reason.

Besides, GDL is a brilliant actor, and RTD is in love with him. I don't see him going anywhere soon, especially not in a five part season so soon after two other characters have died. Also, JG teasing talked about Ianto in future seasons, so...