The thing is it's been argued about Power Rangers whether or not it should be serious or funny. I have to admit that the reason why I watched Power Rangers also involved comedy subplots which later in Super Sentai, some rangers resembled Bulk or Skull. Back then, the so-not-Sentai type characters of Bulk and Skull were added as constant comedy relief involved from one misadventure to another. I believe these two characters allowed Sentai to actually create dumber rangers than they already did.
Of course some Sentai fans dared to berate Power Rangers for being "too campy". IMO Sentai can get funnier than Power Rangers in some cases like Carranger and Go-onger, both awesome comedies. You don't see that facial expression above in PR so often do you?! (Note: Bulk reminds me of that guy... hee hee.) I just find it crazy to berate a show for being funny because I like to watch funny scenes.
As Boukenger gets preferred over Operation Overdrive, some Power Rangers-Super Sentai fans who may like one over the other I believe commented on how funny Boukenger's humor was. I liked the humor in Boukenger and it was definitely a lighter series although it had its serious moments or it's gonna spoil. Above is a picture of what humor PR doesn't have yet.
A reverse kind of happened when Judd Lynn came in for Disney. While Go-onger was a funny Sentai (but strangely it had an apocalyptic finale) it was a rather dark Power Rangers series. Why? Well it takes place in a future where only Corinth is the safe dome and Venjix runs the world. The cast members were serious except Gem and Gemma. In Go-onger, the cast members were basically funny except Hiruto and Mio. I kind of thought that Gem and Gemma should have switched places with Hirtuo and Mio since they are hyperactive characters like the Go-ongers. LOL.
And maybe we should note- despite Shinkenger's serious nature, the show had its rather campy moments especially Mako Shiraishi's cooking. And one thing, Shinkenger had humor that reminded me of MMPR at times. :-P