This game loves wasting your time
this is the core of my review as well. some missions take too long to end, too much bullshit before and after the actual meat of a level; this game just actively gets in the way of you playing it in a variety of ways.
these are the missions with the biggest problems in my experience:
mission 8, retaking of theve II, is jam packed with waiting around, and it gets worse as the mission goes along.
mission 10 pisses me off because it's anti-Ace Combat. the first few times i played the mission i kept trying to fly to airships to destroy them early but they don't spawn right away, and you get constantly bitched at to go back and defend the fleet until the game decides you're supposed to go and shoot the blimps down. this just missed the point entirely of what this series is about. i've never felt so constrained in this series until that part, it's just garbage.
mission 16 is artificially padded with all the dialogue, and forcing you to start on the edge of the map.
this also highlights a massive problem with the in-game cutscenes repositioning you on the map and this is a real bitch in some missions. not because it can screw you over, it's just obnoxious. i fucking love engaging enemies and then getting teleported away from them for story cutscenes.
the end of mission 26 is ludicrous on a replay. you can't skip his fly back to the fucking carrier and you can't skip the landing that comes after it, either (unless you flub it somehow lmao). the game direction took a major hit along the way with this game and it's trying to be way too story rich and the cast just isn't up to it. PA needs to go back and review Ace Combat 5 (for story) and Ace Combat Zero (for missions) for pacing after this. i mean, God damn, bro, the DLC for AC7 is the definitive masterclass of how Ace Combat should be, each of those three missions nailing every single possible aspect that makes the series what it is and that kind of production just wasn't in AC8.
on the flipside, missions 4 7, 9, 19, couple others, are direct and straightforward, but a lot of the seemingly good missions still waste your time. you compare a lot of these missions to just one or two in AC7 and it really sets in how much cruft they needed to cut. go back and play just one AC7 mission like Mission 11 Fleet Destruction (Siren's Song) and you'll see exactly what i mean.
unrelated to missions, the upgrade system is mostly shit, too. i like that it's just based on slots and not that arbitrary point system like in AC7, but most of the offensive upgrades suck dick. why even have "increase standard missile power" and the new "increase standard missile power against air-or-ground TGT" if having both variants doesn't let you one-shot a plane? there are no breakpoints to hit, so this is retarded. oh awesome, i can take down a little ship in one less missile maybe??? might as well just take capacity increases. even the upgrades that supposedly make missiles fly faster, increase homing, don't appear to have any meaningful effect or open enemies up to more angles of attack.