This gets back to the fundamental challenge of time travel in a television series, and explains why Quantum Leap did well and Timeless is currently doing well with a different time-travel story each episode. 12 Monkeys on SyFy is like Frequency, with one continuous, central plot, and 12 Monkeys adheres to this with episodes that are always exciting, metaphysically bizarre, and sometimes over the top.
Frequency has a harder job of this. In 12 Monkeys, our heroes and heroines are struggling literally to save the world - and, in the second season, even time itself. Frequency has a much narrower purview, and it's tough to keep the story pulsing in that more limited frame.
There's also a disproportion between the two major characters - Raimy and Frank - which I don't recall in the movie, in which John (Frank's son) and Frank had more equal roles, at different ends of the seesaw of time. In the television series, Raimy is the more interesting character, but I'm not sure why, since Frank is the only one who can change history - nab the serial killer before he takes Raimy's mother.
There's still plenty of room for course correction and development in the series. I was disappointed to see that Frequency was not picked up for a full 22-episode first season, which instead will be limited to 13. That's ok - there are lots of outstanding 13-episode or even fewer-episodes-per-season series - including 12 Monkeys - and I'm looking forward to more of Frequency.
See also Frequency 1.1: Closely Spun Gem ... Frequency 1.2: All About the Changes ... Frequency 1.3: Chess Game Across Time ... Frequency 1.4: Glimpsing the Serial Killer ... Frequency 1.5: Two Sets of Memories ... Frequency 1.6: Another Time Traveler?