Just to avoid going too negative I will say that for the most part I really like this book. The new talents and armoury stuff are cool. I like some of the small touches like the tau weapons leading to confusion about the kroot's technical abilities and how the necron stuff and the tyranid enemies aren't given their normal in-setting names but ones more like what a human discovering one for the first time might call them. As I'm playing an Intelligence character the Explication system has me excited as well.
People seem unhappy that the Ace doesn't have Fieldcraft. but I've seen nobody complain that the Warrior doesn't get Finesse (linked to many shooty and dodge-y things).
Because warriors are a very generalist combat role. They are not described in a way that would suggest they should be great at any particular skill. The role is for being a generalist fighter and that's what it does by making most combat stuff middle of the road price with a few things cheaper. Their role ability is not tied to a specific skill or set of skills. Everything about Ace indicates that operate, survival and to a lesser degree maybe navigate should be their main skills and yet they lack the one aptitude needed for all of them.
A better comparison might be chirurgeon having Strength instead of willpower. Chirurgeons are stated as being the doctors and the interrogators so not having either aptitude for interrogation is kinda weird. It's just not as big a deal for them because really medicae is their primary thing and they get everything they need for that.
For the record I don't particularly like warriors but not because I think it has the wrong aptitudes for what it is. In my opinion combat specialists tend to feel much cooler than generalist combat characters and having nothing to do in investigation or social situations can get dull. So basically I feel warriors never get time in the spotlight because they are rarely going to be the most impressive combat character in any particular situation, always being outdone by the more focused characters, and can't contribute much in non-combat sections either. I think the role's aptitudes are correct for what the role is trying to represent I just don't think it creates a very interesting character is all.
Since the homeworlds in this book have thrown out the aptitude pattern for character creation anyway I feel like they could have perhaps removed perception and replaced it with fieldcraft. Would keep most of the skills that are bothering Lynata (survival mostly I guess) the same price as they are now but would fix the cost for operate.
Lynata, if you read the character example ace gives at the end I'd say fieldcraft fits very well with that little story, it would probably require stealth to steal an eldar vehicle, pretty crazy high operate to pilot it, maybe medicae to patch up after the crash etc. Also the second ace sample path example of a mounted scout would also fit with survival. I think you are thinking too hard about Ace being tied to navy and/or aircraft specifically, which it isn't. Its a vehicle class, everything from horses and bikes up to starships and everything in between. In fact part of the reason I don't like the role is how bad it fits with navy mechanically because navy aces are much worse pilots than several other character creation combinations.