My experience of this show overall was a move from tentative hopefulness to increasing disinterest.
The protagonist overall feels bland and inoffensive at best. He has clear insecurities about his self-worth and his tendency towards relationship codependency that seem increasingly justified by the narrative's development of his relationship with Zero-Two, rather than challenged or overcome by it. His attempts to self-sacrifice and overcome obstacles are grounded in that reactive insecurity, rather than in his own conscious self-determination. The fact that his name is "Hiro" (literally, "hero"?) almost seems like an ironic label rather than a name for a genuine character. I think his voice actor does a solid job, but the writing feels sub-par for his character, and it doesn't help that his visual design falls well into generic-japanese-cookie-cutter-schoolboy territory. We are generally told about how great he is with little clear showing of how or why, aside from a few vague flashbacks that don't really explain much. I'd be more impressed with what we see of his piloting skills if I had any damn clue as to how piloting in this show actually works. I literally have nothing else to say about him.
Zero-Two is a fun character. She's bold and brash, her body language is dynamic and well-executed on screen, and she gracefully avoids a lot of the most obnoxious boy-girl relationship tropes I've seen in anime (although the show still sets her up for them more often than I'd like). Her voice actress also does a great job. She almost makes up for the protagonist's lack of spark, but frankly I am constantly puzzled by why she seems so attracted to him. The fact that he's the only person who can functionally pilot with her seems like a poor excuse for the amount of emotional attachment she shows, and if anything again suggests a form of overt co-dependency.
Goro is actually an increasingly interesting character whenever he actually gets screen time focus, with some genuine self-determination and conscious decision-making about his relationships and personal aims in life. Ichigo is also reasonably interesting and self-determined, but suffers from the same ungrounded fixation on Hiro that Zero-Two has, although this may not remain the case as time goes on.
The other kids have decent visual designs and aren't bad characters, but I feel like this show struggles to provide sincere screentime to the six(!) other kids to really flesh them out, and so they're relegated to reasonably decent side characters at best, and an unnecessary distraction at worst. That's on top of at least four or so other side characters we see at least somewhat often, who are barely memorable at all as a result.
The art in general is I think pretty high-quality, and the action scenes are pretty fluid. I was impressed at moments by the level of detail in several of the characters' micro-motions and body language, especially in the first few episodes. The direction and cinematography is I think also generally decent, but it lacks some of the flair and emphasis that I think Trigger has managed in their other works. That said, I think part of that is also due to reduced engagement on my part due to distraction by the narrative problems in the story, described further below. Narrative and visual emphasis often go hand-in-hand, so problems in one detract from experiencing the other.
The setting in general feels half-baked. The show has a lot of nods to Gurren Lagaan's style and execution, and I think that's a good thing in general. Evangelion too probably, but I haven't watched that series in depth so I won't comment on it. The mecha designs are over-the-top, reminiscent of Star Driver and by the same designer in fact; whether you like that or not is up to you, but they definitely require some suspension of disbelief as they make little clear technical sense. Everything is powered by "magma energy"(??), which isn't really explained (so far), nor is the rationale behind the boy-girl piloting pairs or the very blatantly suggestive cockpit design. These may be explained satisfactorily later, and there are some minor hints at this so far, but at 8 episodes in, I feel like we've already passed the point of reasonable delay for clearer context.
The klaxosaurs are fine in themselves, but I have literally no idea why they exist or how they came to be, so the fights are somewhat meaningless to me for lack of context beyond "they're dangerous bio-mechanical pests because reasons", so they don't add much to the story beyond overt action scenes. There's also no clear reason or rationale for their various abilities or types, so I never know what the real stakes are in any given fight. Also, we literally never see the cities or people these kids are defending except for maybe two or three mostly still frames, so there's no real sense of what the cities even are or why we should care about their people.
(It's worth contrasting this against Gurren Lagaan, which constantly features over-the-top ridiculousness in its' fights, but always makes it very clear just what is at stake and for who, and why it matters to them - and also makes at least some attempt to ground our expectations in each fight). As well, in all of this, the story seems to take itself pretty seriously; so rather than playing off its' own flaws or making set-ups for comedy, it tries to act as if these plot problems aren't there. Trigger's usual hyperactive charm just isn't present outside of the occasional fight scene or once-off character moment.
There are other aspects I could comment on, like the whole "Father" figure and how that might develop, and also the aspirations of the gropey scientist who appears occasionally, but these plot elements have been left in the background for so long that they feel borderline irrelevant, and that's a bad sign in itself.
In short; my initial hope was that Trigger was setting up a story that featured prominent heteronormative gender and sexual roles and a heavy leaning on codependency, which they would then proceed to deconstruct and subvert later on to provide a more general and powerful exploration of healthy relationships and the ways they can empower and change people. I was hoping for at least one homosexual couple to emerge, and for at least one role reversal with a female and male pilot swapping roles in the cockpit, or at least one case of changes to a mecha's cockpit's design to reflect a different relationship expectation for that couple. At the very least, I was hoping for something action-ey with the same flair and ridiculous confidence that Kill La Kill had.
However, my hopes were seriously jeopardized early on by the instance of overt ass-grabbing sexual assault in the first episode, and later revoked near completely by the clothes-melting klaxosaur which shows up about 7 episodes in (which makes absolutely no sense in context other than as blatant fanservice, and an awkward set-up at best for the narrative sub-plot which follows. Why - WHY - would a klaxosaur have acid whose sole purpose is to harmlessly pass through a complex mechanical chassis and melt whatever the kids' bodysuits are made of? Any suspension of disbelief I had before that moment was instantly gone.) (and in fact, a lot of the lines in that episode made me cringe).
In fact, if anything, the show feels increasingly contrived in how it has set up and justifies these relationships; it increasingly feels like the kids have accepted what are basically borderline arranged marriages defined by their overseers, which they have to make work because they'll die in the line of fire due to poor mecha compatibility otherwise. This is especially blatant in the case of Ikuno and Mitsura's relationship, which seems borderline abusive. In fact, the female characters seem to get the bad end of things in general, as for lack of a clear explanation of how piloting works, they seem to mostly be along for the ride in mostly passive roles, while the males do most of the active control of the mecha (if this is clarified somewhere and I'm wrong, I honestly missed it...). In short, its' narrative thesis so far doesn't seem coherent or sound, and if anything feels confused and possibly just outright wrong; painting a shockingly conservative, exclusively male-led relationship expectation for *all* of the characters, despite having some reasonably strong and assertive female characters in its' cast, and basically making the claim that people who aren't in relationships aren't useful or functional members of their communities/societies (as Hiro continually laments).
The show still has a small window of time to turn itself around and start busting out some interesting dramatic turnarounds, but I'm not holding my breath. As such, it's a show with some strong bits and pieces that are mostly buried by its' mediocre narrative, and it feels like it's somehow trying to be bold and fresh while also playing it safe at the same time, with predictably conflicted performance. I wish I had better things to say about it, as I was excited to see Trigger try a Gurren Lagaan-esque mecha show, but I'm surprisingly disappointed with this offering after enjoying all of Little Witch Academia and a good chunk of Kill La Kill quite a bit.
(The last thing I'll add as an aside is that it's interesting how close in some ways this was to the form of Trigger's previous works. Zero-Two fits the mold of a Trigger leading lady pretty well, and she has a lot more going on than Hiro does even from the first episode. It almost feels like Hiro was shoehorned into the leading role as an awkward afterthought. If the show had just focused on her, and trimmed away some of its' third wheels, I bet the story would have had more zest and focus than whatever it is now. I hope Trigger avoids diluting itself like this in the future.)
Thanks for reading, hope you got something useful from my perspective.