I would love to see the old trip mine plugin being worked out again, as it confuses a lot of people on how to place tripmines at the moment still, so it would be cool to see them come back in that form.
However, I am not exactly sure about the poison shot (if you mean the poison gun), coming back anytime soon, as I recall it produced some issues itself, but if it could be worked out somehow it would be good to be seen back.