Excellent essay on what Power Rangers is, and why SPD sucks:

"PR doesn't just have aliens and wizards, it has alien wizards. Sorcerers using incredible super-technology spanning galaxies and tens of thousands of years. PR is never simply about science or magic over one another, it's about both run together in inventive ways. Up until about Lightspeed and Time Force, PR understood that -- and when TF would try and introduce magic (like Wes' ancient Battle Fire armor), the graft was so jarring over the otherwise unrelentingly tech-y Timeranger that it became downright comical. Forever Red is a great episode -- in a season otherwise bereft of technology or "created" Zords. Taken solely as a part of Wild Force, it makes absolutely no sense. NS and DT were the first time in years PR had again mastered the science/magic balance so necessary to the franchise's ludicrous suspension of disbelief.

As much as we deride season one MMPR (and god knows I do), it was heir to something remarkable. PR was co-developed by Tony Oliver, one of the voice actors and writers on the series Robotech. Robotech grafted three wholly unrelated anime programs together, creating a generational saga about an alien fuel source spanning worlds and two major galactic civilizations. It was incredible. Robotech had the freedom to grab what elements it needed from the source material and aggressively redialogue the material in order to take those elements to the fore.

PR has a similar freedom of scope. Can you imagine doing anything like MMPR with Jetman or GoGoV as the central element? Somehow Oliver had the vision of what could be done with Zyuranger's gorgeous aesthetics and "blank slate" storytelling approach, how two of the villains could be made into flying monkeys and force the fantastic Oz aspects to the fore. And yet, like Robotech was Southern Cross and Mospeda slaved to a reinterpretation of Macross, PR was Dairanger and Kakuranger slaved to a reinterpretation of Zyuranger. PR was such that further Sentais like Ohranger or even Gingaman could be bent almost unrecognizably out of shape in stark defiance to the source material in order to accommodate "PR" elements.

Megaranger was a "space" Sentai that never went into space. I've seen the original concept artwork, with jet harnesses taking the team into orbital battles. It was gorgeous. Saban Entertainment clearly looked at that concept art, looked at the finished high school dramedy Megaranger, and said "fuck it, we're doing space." PR used to be free enough that it could work in utter defiance of the source material and it held together. Most of the sequences in Space that had the Megaship out of Earth's orbit looked awful, but the narrative weight of the program held it together."