It’s as long as it needs to be at the moment, I think. There will always be more to talk about and if you MUST talk Korra, this blog and Korra Nation should help a bit, but…speaking personally, it would seem kind of ridiculous to podcast longer than twice the episodes running time. 

If you like movies, feel free to listen to Devindra on the /Filmcast and Patches and I on Operation Kino. Those are both well over an hour on a weekly basis.