I really feel like both Beast Wars and Beast Machines tried hard to steer the brand more in the course of deep, high concept sci-fi, especially when reading the interviews given by Bob Forward, Larry DiTillio, Bob Skir, and Marty Isenberg (heck, Forward and DiTillio originally wanted Beast Wars to be a Star Trek type show)... but in the end, no matter how hard these people tried, it always came back to people just wanting to see car people and jet people simply punching and shooting each other.
BM tried but I'd argue it failed.
And you know what? Seeing car and jet people punch each other is kind of important. It's the foundational imagery of the first show's first season's title sequence
Conflict is baked into this franchise.
"Autobots wage their battle to destroy the evil forces of the Decepticons."
We can get as deep or introspective as we want, this will always be there and it will always be what most people come to the franchise to see, in some form.
Pretending that's not the case... is like wanting a Batman series where he doesn't take on Gotham's underworld.
Even series like IDW1's latter run or EarthSpark, which take place after the end of the War, still reverberate with the War's aftermath.
I'm not sure fully divorcing Transformers from the concept of conflict and two sides fighting is possible or even desirable. I don't think Transfomers needs to necessarily give the Decepticons their own version of Auschwitz, but conflict in and of itself is part of the franchise.
Eventually a car person and a jet person will have to throw down.
I guess the difference lies between "real maturity" (deep, high concept writing that is thought provoking, emotionally engaging, and carefully crafted) and "fake maturity" (gore, sex, swearing, f-bombs, nudity, etc.).
You're someone whose takes and insights I respect a great deal, and that includes this topic. So please understand I'm not trying to take a shot here... just trying to delve further into this discussion. That being said...
Who decides where the lines are? Everything you've listed as "fake maturity" can and has been done in multiple works across multiple franchises poorly... but they've also been pulled off well in a number of different works.
Just going with sex... sex is an intrinsic part of the human experience. Most (not all, but most) humans are drawn towards romantic and sexual coupling. A work of a speculative fiction nature that wants to capture an authentic human experience with a "mature" audience will explore sexual relationships. That's just realistic and good writing. It's not strictly relevant for Transformers per se, but I hope to highlight that these "fake maturity" themes can be done well.
One of my favourite sci fi shows, the nu-BSG show of the 2000s, doesn't shy away from curses, sex, and violence. And I think it's brilliant. I don't think those elements are why it's so good, but they do make the world of the show feel more authentic. People curse. They swear. They have sex. And, in war, there is violence.
I certainly wouldn't put it in the same category as a work just flashing tits and guns on screen wanting to seem "hardcore."
Circling back to Transformers... SkyBound (the source material for the show that kicked off this discussion) is certainly violent, but it also has scenes of characters trying to cope with the horrors of war, Optimus discovering Earth's intrinsic beauty, a tragic story of how conflict forced Starscream into a life of violence, etc...
And yet "SkyBound is too violent" and "this is just fake maturity, why can't this franchise go back to being kid friendly?" gets tossed at it. Often by people who are happy to praise IDW with allusions to the Holocaust and Stalin-era purges, or TAAII straight up turning a friendly team of rescue vehicle-themed Autobots into the Gestapo and making Megatron an expy for Adolf Hitler.
Like SkyBound Starscream killing one guy is too violent but IDW Megatron committing multiple genocides across the galaxy is "deep and serious and mature"?
I guess I'm wondering where the lines are.
The cynical part of me just thinks that none of this is genuine, people just arbitrary like some things and dislike other things, and rather than be ok with that they try to glom onto reasons to feel morally righteous about their subjective opinions.
But... also... I don't want that to be the case because I think these are interesting discussions to have and I have a desire to assume people are acting in good faith.
So again, I'm wondering where these lines are and who makes these calls as to themes and subject matter?
I hope I made my case that it's not so clear cut.