I think I read on ew.com that they are planning on using flashbacks in The Originals. But as you said, that only gets you so far storywise. Definitely would prefer 4 Originals to 2 or 3 in the cast. And then they've gone and stuck the werewolf chick in the spinoff show too apparently, for no good reason.
Looking forward to the road trip tonight with the professor. I'm a fan of that actor from The Tudors, so I'm happy he's stuck around a bit on TVD.