Indeed, just watched all these on DVD. I was extremely pissed an Nick for busting up the air dates for the series as I ended up missing everything on TV after Black Sun part 1."The Western Air Temple", "The Firebending Masters", and "The Boiling Rock" (parts 1 & 2) have all already aired somewhere in the world, and are thus freely available for online viewing from any number of sources.
This was a very popular show for Nickolodeon, so I wish I knew why they dragged their heels on airing the episodes for the third season, and decided to broadcast the entire second half of the season over the course of one week.
True...but this was Aang's show, not theirs. Don't forget that Katara took out a major antagonist, essentially single-handedly, while they were super-charged from the comet. Not as impressive as some of her waterbending in other episodes, but very clever, and effective.... Katara didn't do a lot with her waterbending skills. They were both a bit more impressive on the Day of Black Sun or other times.
It did look like they're planning some kind of sequel though to cover a few loose ends, like whatever happened to Zuko's mother. They didn't show what became of Azula, either. And I'm curious if Aang would ever be able to re-establish the Air Nomads, or if he really will be the last airbender in the history of that world.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.