Maybe? It covers mostly the same ground, but from a slightly different perspective. There's a reason that there's so much veneration for Sagan because for a lot of scientists today he was the one that opened the door and showed us how to marvel at the universe.As someone who is really looking forward to this show every week is it worth watching the old cosmos?
If Cosmos has done its job and inspired you learn more then old Cosmos isn't going to be of much help. Pick something you're interested in and dig in. There's so much great and easily accessible information out there now. And even a host of great youtube channels that get into some more of the nitty gritty stuff.