It dawns on me that I never actually explained why Areas, Space and Maiming changed like they did. I just mentioned some issues with them offhand but never elaborated on the solution that I came upon. So let's do that now, starting with a recap of why they weren't all that good.
Space was kind of inelegant as far as rules went, choosing where your robot holds its stuff is cool and all but tracking it was a bit of a chore. It helped balance the other chassis types with each other in making some of them arbitrarily better at being able to equip more or less parts in some or other spots, but at the same time it meant a few arbitrary restrictions on unconventional, yet perfectly fine otherwise, builds.
That worked for a while decently enough, but Maiming complicated things further. The first few maims were the most important ones, taking away the most important equipment of the victim, and making the rest of the combat a nearly-insurmountable uphill battle for whoever suffered the first one.
The game is about (or aims for) intense, back and forth combat, gradually building up to a desperate climax. Two robots reduced to no weapons bashing each other with their battered limbs is cool, but a futile struggle of one character as the near-mint victor toys with them is a pointless, drawn-out slog.
Now I guess I could just do away with both space and area restrictions, and maiming in general, but it is a big part of what makes mecha combat feel like, you know, mecha combat. Obviously I could not just do away with them.
Now to the solution: Everything can go anywhere, you only need to worry about making every area important by keeping them balanced with each other. This enables off-the-wall designs slightly better, specially with the custom weapons engine. Without some limit on placing stuff, you will always have dead areas
that you don't care about losing. That's bad and antithetical to a game
where every turn is supposed to do something meaningful
Choosing which Area to sacrifice as you get maimed helps with that, because you will not choose an area that you need in order to keep fighting. Defender-side maims are also a lot more badass, because they let everyone describe how damaged their robot is, while still standing and being able to fight. While we're in the subject of narration, it also helps make that flow better. You make an attack, and the defender describes the damage dealt along with their reaction after noting down the damage they take.
Much like with unrolled Penetration, it helps make the game run smoother. It even gives you the tactical choice to either bunch up your good stuff somewhere it'll be safe until the end, or to make a couple sets of key areas and sacrifice the lesser useful ones depending on the situation. It is a bit of a change from how it used to be, but it is for the better, and works very well in mitigating the generally stronger offenses that everyone starts with. If it is absolutely necessary to do so, you can always use a controlled attack to pick off a specific Area, even.
The only issue is that you need to spread your weapons all over the body, which often means placing stuff in the head when you'd rather have those guns on the arms. This is, fortunately, a problem of flavor and not of mechanics so it can be solved without a lot of fuss. Head, Arms, Torso and Legs could become Left Arm, Right Arm, Shoulder-Mount and Chest-Mount for instance. Or it can abstract placement and be more functional instead, with the Areas being Held Weapons, Mounted Weapons, Defense Systems, and Utility Equipment.
So with having four unnamed, generic equipment slots that can be renamed to anything you want and some guidelines for making them tick, things should be set. I am, however, intending to write in a chapter with several alternative rules after the ground level content is changed, and there will be an alternative Area/Maim system in it.
Edit: This is a flavor-based change. It is, however, entirely possible for one to not like the way this works rules wise. There's hoops to jump, and some people aren't too fond of hoops. There's a wiser designer than I who says that if you fight human nature, human nature tends to win.
So here's the deal. We can lift the restrictions on placement entirely, all it would mean is making sure the game doesn't get too imbalanced as a result. And while I'm not a fan of what I'm about to propose as a solution, it gets the job done:
Random Maim Locations Table
aka Look on my works, ye Mighty, and despair!
All Upgrades and Weapons that aren't exclusive to the Core can be placed in any Area of either Head, Torso, Arms or Legs. When a Threshold Level is lost and an Area is to be Maimed, said Area is chosen at random depending on the last digit of the Total Damage Dealt dealt to the Maimed Unit:
1 = Defender's choice of Head, Torso, Arms and Legs. You cannot choose an Area that has already been Maimed.
2-3 = Head. If the Head has already been Maimed, it is an Area of the Attacker's choice on a 2 and the Defender's choice on a 3.
4-5 = Torso. If the Torso has already been Maimed, it is an Area of the Attacker's choice on a 4 and the Defender's choice on a 5.
6-7 = Arms. If the Arms have already been Maimed, it is an Area of the Attacker's choice on a 6 and the Defender's choice on a 7.
8-9 = Legs. If the Legs have already been Maimed, it is an Area of the Attacker's choice on a 8 and the Defender's choice on a 9.
0 = Attacker's choice of Head, Torso, Arms and Legs. You cannot choose an Area that has already been Maimed.
Randomized results means that attempting to optimize Areas so you won't be affected by Maims is about as likely to hurt you as it is likely to help you out. There is a slight bias for Defender's choice, Head and Torso Areas but it is negligible, really. Instead, you can focus on getting your unit just right and give it whatever you want, without worrying about the effectiveness of optimizing your Areas. It might work out fantastically, or it might not! Good thing there's plenty of healing to work around a key Area getting chopped down.