Americans Hate Tingle: Some Western Toku fans hate Go-onger for its absurd wackiness and over-the-top slapstick comedy. This has been changing in recent times, but whether it's on its own merits or because Goseiger, later changed to Go-Busters, which in turn later changed to ToQger, and then changed to Ninninger, is the new fandom punching bag is a debate best left for another time and place. Not helping things is that, much like Goseiger, both it's predecessor (Gekiranger) and the next Sentai completely overshadowed Go-Ongernote in the case of the latter, it's due to Disney deciding to air a Re-Cut of Mighty Morphin' Power Rangers instead of adapting Shinkenger, resulting in many fans watching the latter, which caused the series to become a Gateway Series to Sentai for many, although it wasn't nearly as bad for Go-Onger as it was for Goseiger, since the two "Rider" series Go-Onger ran alongside (Kiva and Decade) weren't as well-received as the ones Goseiger ran alongside (Double and OOO). Despite Go-Onger's relative unpopularity in the West, it was apparently popular enough in its homeland to receive a "10 Years After" special like Hurricaneger and Dekaranger.
Anti-Climax Boss: Yogoshimacritein. Despite all of his ramblings about his incompetent son, and his sucess at eliminating 4 of the Go-Onger, the Final Battle against him, both before and after the Industrial Revolution are extremely short, with his normal size failing to stop the three remaining member at destroying the power cog, and losing to the reunited team member, while his giant mode get curbstomped by Engine-Oh G-12 Finishing Move.
Awesome Music: A lot of tracks. Go-onger has a really nice soundtrack in general, but to specify:
Evil Is Sexy: Kegalesia. Period. The fact that her actress is a former AV * "Adult Video" star doesn't help matters. It's no wonder that she labels herself as "in charge of Gaiark's sexiness" whenever G3 Princess is around.
Saki's interactions with Miu are taken as Les Yay by some.
Memetic Mutation: In Japan, pictures/videos of Gunpei (or characters imitating his "Dash Dynamic!" pose) are almost unfailingly responded to with "Kakkosugiru ze..."* "Too cool..." in reference to Gunpei's final words to Gunpherd in GP Final.
Tough Act to Follow: Sentai fans weren't entirely on-board with this season, primarily because it came after Gekiranger (Which is loved by Western fans). Speaking of Western fans, many who watched it after RPM weren't fully on-board with the direction taken.