Anime Nobody's Favorite
The elephant in the room when talking about Frontier is the whole Henshin Hero gimmick, to the point that pretty much every defense starts with "once you get past that..." But the fact is, there's a reason Henshin Hero is a trope; the idea is a well-trodden field. And if you judge Frontier by the standards of a Henshin Hero show... it's not great. Not awful, bar the end arcs. But when you take out the central gimmick of the series, you're supposed to replace it with something.
Frontier's human cast is one of the smallest of any series, and that, combined with the show's gimmick, feels like it should lead to some really good character development or dynamics. But it just... doesn't, really. The characters are bland and archetypal, and most of them don't really change much - or, if they do, change in a manner you could guess at from their first focus episode. Takuya in particular feels like the middle of a Venn diagram between every other protagonist. Character work's always been a strong point for the franchise, and Frontier is just not good at it.
The formula for most of the show is the tried-and-tested monster-of-the-week one, but it goes on just a little too long and the villains just aren't that interesting. The plot of the Ten Warriors and Cherubimon goes on for so long that by the time the Royal Knights show up, it feels like a bizarre postscript - and their arc being entirely wretched doesn't help matters. Lucemon himself is a pretty good villain, but he shows up far too late. And it really doesn't help that the "human/beast" division that the show plays up so much ends up amounting to essentially nothing. There's just nothing to set it apart.
Now, is Frontier a bad show? Not really. But I don't think the dislike it gets stems entirely from its gimmick. A good series can make people love it in spite of breaking from the formula, so long as it proves itself in its own right - look at Beast Wars or Casino Royale. And Frontier doesn't do that. It's a very okay series, with the lackluster fights and animation Digimon tends to have, stapled onto what you would get if you told a computer to make an anime series. "A show about transforming teenagers who fight God? You've done it again."
Anime Worth the time
I like frontier. It is different from other seasons, but what's wrong with that? It was a pretty interesting journey throughout, the lack of partners meant less characters to keep track of, but added a depth to the humans. The Royal Knights are was probably the worst part, if only because it took so long. It was practically the same thing over and over, except one or two episodes put a spin on it. But watching it, the heroes do better each time, it's just not until the end that they finally reach the point of victory. And when they reach Lucemon, the big bad, and the other kids are able to help again, it's awesome.
Really, give it a chance. It's a good series.
Anime Not as Bad as it Looks
The shifting from having Digimon partners to turning into Digimon isn't a bad thing.
True that's a great change, but once one thinks about it- it's actually pretty cool. This method of Digivolution actually puts the children into the battle, putting more at risk and making the fights just a bit more interesting. True that Tamers did it first- and in a better way as it involved the kids actually fusing with their partners to become one- but Frontier was a new season and that meant that the writers wanted to take something new and run with it.
The show in general has rather average animation mixed with great voice acting. One can easily see that there are two different art styles used and it switches in between episodes, with one being used more than the other. Stock Footage is clearly abused, but there are a few fighting scenes that are worth watching, but there are also fights that seem to either draw on, or there isn't enough movement, and to be frank most are predictable. On the other hand, the voice acting is great- especially since the dubbed version uses voice actors such as Michelle Ruff, Steve Staley, Crispin Freeman, and even Daran Norris.
Where the show falls down hard though is the plot. The first half of the show was decent- saving the Digital World. Sounds simple enough. A few episodes were fun, the characters are entertaining in their own way, and plus this season has one of the most complicated and compelling family conflicts in Digimon history.
The second half though was just awful. When we see the new villains The Royal Knighs, and hear about Lucemon- we expect more from the next 10 or so episodes rather than the same battle over and over again. Which is what the second half is for the most part- the characters use their new ability to turn Takuya and Kouji into their supermode forms in order to fight the same battle that we all know they are going to lose. Not only is the absence of participation from the other characters not fun, but neither are the repetitive battles. It isn't until the end when the fights become interesting again.
The season itself is not perfect, but if you're a fan willing to give it a chance- or someone who just likes the character designs-it's worth a try. Though once you reach the Royal Knights, just skip a few episodes if you don't want to bore yourself.
Anime Worse than Zero Two
I did not think this was possible, I remember watching Frontier as a kid and I remember liking it. But after rewatching it, this season makes Zero Two seem like a masterpiece. As broken, inconsistent, plot-holey and unserious as Zero Two was, it did something right: it kept me watching.
The one word I can describe this season as is: boring. Every episode I watched, I felt like I was wasting my time. Generally, they use the same formula: Takuya and gang arrive to new place, they get involved in the issues of one-shot characters, they find a new spirit, evolve, one-shot character issue is resolved, roll credits, rinse and repeat.
The season barely has a plot that, when the writers are not feeling like writing the formula I just described above, gets all of its info dumped into random exposition-heavy episodes. This makes practically 90% of the episodes worthless. Unless you like watching "let's save this random village of whatever" being retooled over and over again.
The characters are all knockoffs of Adventure's. Takuya is Taichi, Koji is Yamato, Tomoki is Takeru, Izumi is Mimi and Junpei is... Daisuke, I guess? I mean, his only character is that he spends most of the time trying to impress a girl. At least, he's less annoying than Daisuke, I'll give him that.
These characters barely develop or are even given a reason to do the things they do. So, they're called to the Digital World, they almost immediately die, they just so happen to find their spirits and then they decide... "Meh, I guess I'll just do what this random voice on my phone says." For no reason whatsoever. It is never elaborated on why all these character decide to stay on the Digital World, why they are trying to save it, the justification is always "for reasons."
The writing excels in how bad and generic it is. I thought Zero Two was bad, but Frontier is just sad. From the recycled storylines to the way the show handles any character that is not named Takuya or Koji, and even them feel like generic sentai rival dynamic characters.
On top of that, someone on the writing must've hated women, because Izumi has got to be the most pathetic female main character I have ever seen. She gets her ass kicked in her debut episode, one of her special attacks is bumping her butt into her enemies, which does nothing except make them horny and whenever they fight together against an enemy, she's always the first one to be taken down. Worse than that, she'll spend whole episodes on the sidelines, because she gets her spirit stolen.
The villains were just silly and non-threateing. Coupled with the bad writing, because there were many times the kids and the villains could just evolve and easily kick each other's asses, but didn't. Why do they have all these spirit evolutions if they never use them? I lost count of how many times they let themselves be beaten by the enemy simply because they decided to stick to an inferior evolution for no goddamn reason.
Are there good things about Frontier? I guess some of the soundtrack. The opening theme is great. And although many episodes are total filler, it feels good to explore the Digital World, as bland and uncreative as it was in this iteration. Other than that? This season is just insulting to the brains of anyone over the age of 18.