So far I can't help but think that some PR loving friends of mine were actually Sentai fans (which one they like better I don't care really) gave some positive views of Boukenger to even compare its goodness to a Saban season that is like Lost Galaxy (but Lost Galaxy is more serious than this). Why I think it's the case? Here are some:
According to DancingAlienDude, he feels like the main characters are as likable as the MMPR cast. I agree although I can only see Power Rangers similarities to Satoru (Tommy), Souta (Billy and to an extension Kai of Lost Galaxy) and Sakura (Kimberly and maybe with Jen from Time Force but she's sweet as Kimberly even if she's tough). I kind of thought that Masumi is like Leo in Lost Galaxy and Natsuki is more likely a parody of Maya in Lost Galaxy. As for Eiji, I think he's probably another tribute to Tommy or maybe to Ryan in Lightspeed Rescue who was an original ranger by Saban.
I don't know but some of these Power Rangers fans actually compare him to Zordon although DancingAlienDude likes this artificial intelligence being better than the other even if he turned out to be nothing more than an "it" given life by Leona Giordana who actually created him as a simulation to take care of things if she's gone noticing that his behavior is too different from his creator.
I think the lighthearted humor may have done a great factor. Some fans complained about the corny humor of the Disney seasons.
I think it has to do with the villains being more well-developed.
I think it also has to do with the plot is more detailed especially with the heroes and the enemies due to the fact there's just enough episode count to do so. Operation Overdrive was rushed.
Or maybe it had to do with the wacky and goofy guy Morio Makino. I honestly can't help but think of the hilarious Professor Phenomenus except he's actually working with the rangers. Goofy guys like him make PR/Sentai good especially if they're working with the rangers. Too bad though he doesn't have bumbling assistants with him like Bulk and Skull.
Or does the team-up have something to do with the likability factor to Power Rangers fans? Maybe. I kind of thought that the humor, action and drama of the "you decide whether its canon or not" vs. movie Boukenger vs. Super Sentai was well-done although Gaoranger vs. Super Sentai was WAY better for me though.