In principle this is a good idea. Riders often kill needed laws. However, keep in mind this specifies appropriation bills only. So for another kinds of legislation it is business as usual. I suspect if this does become law the legislators will eventually title their bills so broadly they will still get away with hiding pork barrel projects or attaching clever ruses like defunding planned parenthood. I look for this to be effective for a short while so for the sake of additional transparency I would support it.