I think originality and lack of originality plays a huge role amongst why fans can be so divided. Some fans say that a Power Rangers season is good, if it has more originality. Others say that Power Rangers can only be good if it stays true to the source material.
But for starters, let's take a look. What describes Power Rangers?
We know that Super Sentai is described as a show where a team of three or five color-coded heroes fight evil, using teamwork and giant transforming mecha. Super Sentai has a new setting, characters, themes, and stories every year.
So what describes Power Rangers? Is it the exact same as how you would describe Sentai? Well, yes. But there's one more element that's added to it's description. Power Rangers adapts from Super Sentai. By using it's costumes and source footage material. Because of the source footage, Power Rangers must follow the same formula that Sentai uses. And that includes giant fight scenes. Plus, the companies will get more money in their pockets from the U.S. for toy sales. :P
So let's see. The people making Power Rangers can do whatever they want to do with the show.
Do they HAVE to use the costumes made in Japan? Not necessarily. After all, Power Rangers got some original costumes like Lord Zedd, Divatox, Astronema, Dark Specter, Trakeena, Ransik, Mesogog, and the Titanium Ranger. However, because Power Rangers has always used the same costumes from it's Sentai counterparts, it has become a bit of a staple for the franchise to use them as part of Power Ranger's image to make it what it is. This goes the same with the fighting footage. Though this does save the people a lot of money. :P
Power Rangers is basically a fanfiction to Sentai. It should use the source material. And with it, make it's own characters and stories. That's what makes Power Rangers what it is.
So with all that talk about using Sentai materials in the shows out of the way, lets get on with the BIG debate in terms of originality in Power Rangers. This would be the characters, the plots, the themes, and the stories. Why would some fans hate the originality in Power Rangers, compared to those that would praise it? I will be making a couple posts that will go over the Saban and Disney seasons, for in depth analysis for each season.
Fans love originality in Power Rangers, because it can show that Power Rangers is it's own show, having elements that Sentai does not have. Which is why MMPR, Zeo, Space, Lost Galaxy, and RPM have been praised.
So what about the seasons that copy a lot from it's Sentai counterpart? Some fans say they're boring to watch, as it's just more of the same. However, other fans love to watch them regardless. There are two main reasons. One, it's because they view it as an English translation of a Sentai they might not be able to watch, and that this is the best that they will get (something that the more original seasons couldn't do). And two, fans believe that the difference in cast is more than enough to make the seasons enjoyable to watch and to make them their very own shows. Because of this, Lightspeed Rescue and Time Force have been praised. This is how you can either like or dislike a Power Rangers season that's handled this way.
I will be sure to get the other two posts up so we can go into more detail for each season. But on this post, I wanted to point out the main pieces of information, and to explain why both originality and unoriginality in Power Rangers can be both enjoyable and unenjoyable among fans. This debate tends to play a role in affecting how fans of both Sentai and Power Rangers view each Power Rangers season.