The entire premise of Rip Hunter’s vendetta against the immortal madman was solidified early, and the season never really felt like it was building to anything other than the final confrontation.
Juxtapose this plot set-up with the events that transpired during the first season of Legends of Tomorrow, and you will instantly notice the difference.
Essentially, every episode was a procedural that more or less followed the same narrative beats, and it became tedious.
Even with its abbreviated first season, Legends constantly struggled to maintain narrative momentum last year, and much of that had to do with the fact that the threat of Vandal Savage was established and thoroughly laid out by the time the credits rolled on the pilot episode.