Well, too bad for you. Gokaiger wasn't what you wanted to see, but there's no objective measure of "better" or "worse." I liked Gokaiger for its fanservice and I value it much more for being enjoyable to me than I value some series that are supposedly better written. It's like people go "but Boukenger was so much better, it had its own story" And? For me, the characters were awful, the story was dull, I could've done without it. Not so for others.
Lazy, let's get one thing straight here. We'll be getting another when I get to your second point.
I am a writer. I care about good, consistent characters, fun engaging plots, and productions that can pull off entertainment to a degree that I enjoy. This is a subjective thing, of course, but there are some things that are not as subjective.
I've never seen Boukenger, so I cannot comment. But Gokaiger had a story, and it had some interesting villains-it just did nothing with them. Blue's mentor/friend being a cyborg used against him could have been great, dramatic, whatever. It was underwhelming and felt like they pulled a lot of their punches.
The leader up to the turning point of the series secretly wanting to be respected when he had appeared a fop could have been interesting if they explored it before he died.
The big bad was the guy's father but that barely mattered beyond giving him a reason to come to Earth, and the way he was defeated, and his Empire for that matter, was lackluster considering how much they were hyped at the start of the series.
But the show isn't just about the villains, and I know you have this weird thing about not wanting villains to be all that important.
It's about the heroes.
Which brings us to the aloof possibly amoral Red, the stoic Blue, the wacky silly Green, the Girly Princess Pink, and the hot headed tomboyish fanservicey Yellow. Who is also greedy.
And ultimately the even sillier fanboy Silver. That's all we have to work with beyond the fanservice.
The fanservice makes up the grand total of the series, but it is subpar fanservice.
The past heroes are little more than macguffins at best, there are little to no homages to past series, either in what the Gokaiger bring to the table beyond the obvious or in what the villains bring to the table, there are no returning villains, there is really nothing beyond returning heroes and the Gokai Change.
Compare this to the show Mebius, which like its story or not, it did the whole anniversary series thing better by definition.
Purely because it went the extra step over Gokaiger, in the same way that Gokaiger went over Decade.
Mebius was filled with homages to the past. Old villains returning, old heroes appearing and mattering, old technology being reused, hell even just ideas or scenes was brought back gloriously. Capsule Monsters, Mirai doing the transformation call of one of the past Ultras randomly, the files of the past monster fighting groups...
That's something I would have liked from Gokaiger. If it's going to celebrate, why not go all out?
Your complaints about "stereotypes" and goty's point that pretty much all Sentai up to a point feature flat/stereotypical characters brings me to something else I wanted to address: I get really annoyed at the assertion of some fans (I am not aiming this at anyone here - I've seen it many many times) that modern audiences are somehow vastly superior to 70s/80s/90s audiences and just won't tolerate stock plots or generic characters any more - then they get upset when Sentai continues to do pretty much as it's always done. If you really are hung up on wanting to see thoughtful writing or production, only a very few shows will appeal to you.
I'm glad you brought up that you're not aiming this at me, because I vastly prefer the 80s Sentai to the Modern Sentai.
It had a lot more of an edge back then, tempered perhaps with the way the effects worked, and they didn't try to do the silly characters as much. They just told an enjoyable plot for a kids show and had some great action, which is all I really want.
If you make your characters a big focus of the show, which a lot of older Sentai did not, then I had better be able to enjoy them or your action better be able to surpass them.
Modern Sentai, more than not, fails at this for me. Something about it feels off to me.
This isn't to say that I like all old school Sentai without question. Far from it.
It took a while for me to get into Maskman, and that was after trying to watch it a few times over the course of months. But once I got a few episodes in and realized what the show was going for, specifically the God Hand episode, it started working with me and made a lot more sense.
Bioman I am a fan of because it's just a good adventure from the start with a convincing villain and pretty nice powers and a reason for them to be heroes.
Liveman won me over with its story and characters and keeps me interested with them, and the more random adventures they have, despite other grievances I have with the show.
...and that's really it for the Sentai I love. ZyuRanger may join the list just out of me loving the Mecha so much, but I haven't seen enough to comment. Changeman may also join that list, I haven't gotten to see it yet.
Jetman? I hate Jetman. I hate Jetman so much.
Which is weird, because I'll flat out tell you-the Gokaiger Jetman episode was the best episode of Gokaiger to me.
Sadly that Gai is not the Gai I have to sit through in Jetman.