Flit's Arc- This is probably like, one of my favorite arcs in Gundam, I think the art style is the only thing from making it seem as dark as it is. First episode starts with a young Flit watching his mom's lower half crushed, then obviously burn alive infront of his eyes after he gets the AGE device from her when the Vagan attack the colony. He's super serious about building the Gundam, he grows alot as a character in this arc alone and aside from the episode where him and Yurin are skipping around in the forest for a few days he doesn't really go around doing kid stuff, he's focused on the task at hand. Emily is pretty annoying but she has good reasons for wanting Flit to not fight and you see alot of the young annoying angsty protag stuff coming from her rather than Flit.
Things that annoyed me though
1) Vargas won't let Largan pilot the Gundam because it hasn't been tested and he's not trained for it, Flit's saying it doesn't matter they are under attack(logical), Vargas still says no. BITCH THE VAGAN ARE ATTACKING YOU, THEY AREN'T GONNA JUST LEAVE AND LET YOU CONDUCT FIELD TESTS SO YOU CAN BE READY NEXT TIME. I mean it's obvious the creators just wanted Flit in there but it really irks me that with all the other bullshit that results in the protagonist ending up in the mobile suit cockpit in Gundam, you had a more experienced pilot ready to fly it and Flit saying yea let him fly it, and it didn't happen. I mean granted Flit is Gundam Jesus in his series but this really bothered me the second time through in hindsight.
2) Grodek not being introduced as a genius programmer until he gets to Fardain is a minor pet peeve, he was able to trace some guys hidden account and disable the ship's connection to the Federation network without much explanation until this point, where if you actually remember you go "OOOOOOH", but first time through I didn't remember either of those events since I watched the show week by week. If they started off at some point having Bruzer mention his genius programming and tactical skills in one of the first 2 episodes it would explain abit more how he did those things. Again not a major issue, just a minor pet peeve rewatching it.
Asemu's Arc- or as I call it Daddy Issues Arc. Flit is really a terrible fucking dad. His sole mission in life is to destroy the Vagan, and he tries to instill this in his son, essentially shaping his life. Nothing Asemu ever does it probably gonna be good enough for him. He has a great battle, and Flit tells him he could have shot down 4 more suits if he aimed better. Really dude? Scumbag Flit, no wonder Asemu has problems. This arc pretty much took on a Goku/Gohan/Piccolo dynamic from DBZ, where Flit is awesome but the absentee father and Woolf ends up having to nurture Asemu into becoming a proper man about halfway through. I still really like this arc though, the Zeheart/Asemu dynamic is a good one and having all the main supporting cast from Flit's arc carry over adds some actual value to certain events and peoples death. Asemu finally grows up near the end and Flit is pretty strong in his own right in this arc, in more than just a mobile suit. Also we got the Super Pilot and Super Pilot theme, which for some reason has been pulled from Youtube, along with the Super Pilot scene? Tragedy.
Romary kind of came off as initially liking Zeheart more, that was a weird love triangle and probably unnecessary. She needs to just accept her fate as a female Asuno family member who will be unhappy in some manner, whether its getting crushed by a building and burned alive, marrying someone you've crushed on since childhood who will never let you be #1 in his heart, or marrying and having a seemingly happy family only to have some super robot from the future past leave you as a single mother.
Kio's Arc- God damn you so much Kio. Watching this arc again still angered me. Kio starts out PERFECTLY FINE, even with Flitler channeling his normal old man ignorance and racism into his hatred for the Vagan, he was still a normal kid who just wanted to stop the Vagan that were destroying Earth when it finally happened. He's apparently a top-tier X Rounder according to Flit and that combined with the training means he can use a suit, ok.
Shanalua teaches him some VERY BASIC battle things like keep moving, never be unguarded when you attack, etc. He uses this in the desert battle to win. I initially went "ok so she's just telling him stuff that he'd learn from experience had he been an actual soldier for awhile", and then the Vagan Brothers are totally surprised by his constant dodging, calling him 'clever' for it. Like maybe in the context of Gundam AGE this is clever, cause alot of fodder grunts just stand and shoot their lasers and either shoot the enemy down, get shot down, or both, but dodging alot to avoid attacks should not be a surprise to you, especially when you've had like 3 battles in this desert alone before Kio rolls on in. This is why he dies to Seric in a basic Clanche Custom in the end, he sucks.
So they go to space, get jumped by Super Pirates led by Super Pilot, he kind of gauges whether they are worthy of the AGE device. Flit does more actual captain duties since the actual captain of the Diva has had 1 actual captain moment since this arc started, and that was back on earth. I'm not gonna type out a seperate nitpick on Captain Natola, she just sucks outright and idk why she was written the way she was, she's really useless and had to have their captain moment from the end of the series like, back on Earth. So Second Moon happens, I don't mind this cause it actually gives some insight to the Vagan and how they live. Then Super Pirates come and save Kio. THIS ARC IS ACTUALLY TOTALLY FINE UP UNTIL THIS POINT, DESPITE SOME ISSUES HERE I LIKE IT. Then the series just shits the bed and i'm not gonna nitpick everything after this point cause it's alot and tldr of the second half of the arc is that its poorly written and rushed ending that destroys 2.5 arcs worth of work.
Now right before the final battle we are left with our first protag in Flit who is the extreme evil in that no matter what he wants to destroy all Vagan no matter what it costs. We have Asemu who is pretty neutral in this sense, in that he will kill someone if he has to but he knows cause of Zeheart there are good Vagan out there. He focuses his years on destroying the Vagan influenced Federation ships and searching for EXA-DB, to keep 1 side from becoming too strong because he knows what will happen if Flitler gets that tech too. Then we have Kio who is now super pacifist Kio, and endangers those close to him so some no-name Vagan pilots that want to kill them all don't die because some sick people he met on Second Moon were nice to him. This dynamic seems to have been obviously deliberate but I think that having the last main protagonist be the one that wants to save the Vagan, in the way they wrote it was a poor choice cause it just makes it frustrating to watch.
Having the Flit viewpoint at the start made perfect sense, and in hindsight having Kio's viewpoint for the middle one would have made even MORE sense since it would have been the other extreme, and Zeheart was trying to capture the Gundam at 1 point anyway to get Asemu to come over or quit, they had the chance to plug Second Moon in there. Then having the neutral rational mindset of Asemu in the last character be what brings it all together. I could easily see Kio being a pirate that disables bad Federation ships and Vagan ships for a decade. An Asemu type character who is both taught by Flit to hate all Vagan, and then have this father telling him that the Vagan deserve to live would have balanced out. Pacifist protags in Gundam are stupid, even the ones who are classified as one will kill people, they just don't choose to if they have to.
tldr of above First arc is really solid on its own, second arc is solid based on the arcs MC and supporting cast coming over from first arc, third arc slowly lets you wish you never watched it but at least you will get to see some really awesome mobile suit designs from both sides. Seriously, MS are amazing in this series.