Actually (nostalgic nerd mode engaged) the Dairugger footage was added to complete the season, much like Robotech. Fleet Of Doom was an original movie, not re-edited footage, as WEP had done a second season of Lion Force on their own, later re-shown as "The New Adventures Of Voltron" just before The Third Dimension started airing.Speaking of which, Lotor brought out his own Ro-Beast Voltron in that show, so they did it before Voltron Force. As for Voltron Force I didn't get into it, but while I hate the intro the show itself didn't seem too bad and I wouldn't be surprised if it found it's own audience like the current Ninja Turtles cartoon, which I also can't get into but I've seen enough episodes to know it's a good show.
If you want to see a GOOD Voltron series, I highly recommend Voltron: Legendary Defender, which is on Netflix right now. It's made and animated by some staff behind Avatar The Last Airbender and Legend of Korra, namely Studio Mir, Lauren Montgomery, and Joaquim Dos Santos. It is soooooooo good! There's a second season soon to come out, but 11 episodes are out and it's awesome!
Oh, also, the new DreamWorks series isn't a continuation, but a complete reboot.