[Matrixbeast]

I'm haven't watched much of Ninninger, but I feel that the reasoning of "It's getting better! I promise!" holds little weight when everyone is viewing it at the same time.
This isn't a case of years old series that people have seen before like Zyuranger, Dairanger, or Goseiger, where "It gets better" is something that many people already know and can attest to. If you feel the series isn't holding your attention or is just a grind to watch weekly, feel free to drop it.
If a series isn't interesting the viewer, and watching it seems to be more of a chore, they shouldn't feel shackled and continue watching just because someone else insists they do.

As for breaking the mold, internal conflict can be found in many Sentai since Jetman, the most recent that comes to mind being Goseiger.