I could see doing Rip Hunter and time travel for a couple years, but not Vandal Savage. That would get old to be going after him for a couple of seasons. I also wonder if they will do the full 20 some episodes next year, or just do a partial season. This show might function better as a half season show with a different goal each year. You could also swap out characters as they introduce new ones in the other shows
I have watched Legends of Tomorrow from episode 1. I like it (NOT love it like the Flash). However, I really enjoy the development of Leonard Snart (Captain Cold). He has been a pleasantly surprising revelation.