So Chris walked in a bar and ended a discussion...
Structures
This is a generalized thing, and would include all of the immobile stuff EXCEPT for turrets. Turrets need to have one of the four main classes, since they are combat-oriented, and thus bombers are not just the answer to every turret situation ever. That would be an example of going way too simple.
On the other hand, “simple” things like fortresses and other semi-stationary stuff that is high-health and structure-like would simply be marked as a structure, because that’s part of the important role of bombers. It’s important for you to guard the bombers during combat as they complete their run, and that’s fun.
Strike
This is the “most basic” class in a lot of ways, and it’s fighters as well as a variety of other types of ships that are highly mobile and generally best at shooting other things that move.
“Air superiority” is another common term of this, or sometimes assault craft.
These are the primary counter against bombers, just as in real life. These also outclass the smaller and more specialized “blitz” group, which includes the melee units, shorter-range specialized for things like parasites, and other particularly-strange stuff.
Bear in mind that just because the Strike class is going to beat the heck out of the Blitz class, that doesn’t mean the Blitz folks aren’t going to inflict some… oddness… on the Strike group. Aka, parasites may have captured a bunch of fighters. An autobomb may have done extra structural damage despite its death. Etc.
Bombing
These are mostly anti-structural units, and given that that’s a fair part of the game, that makes these important. But in the core quad of actual ship-on-ship combat, these guys come up a bit short, which makes sense given their outsized role in the game at large.
That said, they still are a very important counter to the Archer group, which otherwise is going to eat up your Strike class, so it’s not like you don’t want these around. They simply are useful against a much smaller set of combat ships than Strike or Blitz ships.
Archer
A name that is thematic for these guys is tough. But overall their distinguishing feature is some degree of precision-striking over a longer range than normal munitions. So these are great against Strike craft, because they’ll generally destroy them before the range can be closed.
However, these are less effective against the hulls of both Bombing and Blitz ships, because (thematically speaking) they have anti-archery materials or whatever. 
This lets those close the distance and eat the poor corvettes (formerly missile frigates).
THAT said, shelling stuff from a distance is both useful and fun. It thus only makes good sense to give these guys a secondary role as well (like Bombing class). This also does the double-duty of making it so that bombers are not SO central to the entire freaking game. Two things to guard, rather than one, depending on the context!
These are thus good against the “Scary Generalists,” which are basically big “I kill everything” kinds of ships. Nothing is particularly good against a scary generalist, because one-on-one it kills everything. However, if you’re going to throw your resources into something to combat these… throw those resources into Archer ships. They are in no way a hard counter against those scary generalists, but they are “the best of the things that are bad at it,” which is, after all, pretty good when you’re facing a golem or whatever it happens to be.
Blitz
This was a hard group to come up with, because it’s not part of the core triangle that was pre-existing in AI War Classic. However, the core goal of this class is that is that they are probably short-lived (comparably) but inflict a lot of damage on a variety of things.
It is fitting that the “air superiority” type of ships would eat these for lunch, since that’s part of what air superiority means. But these guys then being really good at carving holes in everything else (possibly at an outsize cost to themselves) makes them threatening and relevant.
Scary Generalists
Golems, Major Weapons, etc.
... Then a new discussion started.
"
How do we convey that to new players?"
(And most veterans will be "new" for that specific mechanism.)
First, I dislike the "blitz" name used here. I think it's confusing with "strike". I propose "specialist", as this better convey that they win with tricky stuff instead of fast attack. Also, I think it implies they die fast, because... I don't know. Don't you feel that too? (I imagine I could tell a friend about a FPS game with classes and say "This class is the specialist. It has many weird weapons but dies fast." and the friend would reply "Obvious.")
I rather like the names for Strike(r), Archer and Bomb
inger.
"Scary Generalists" need a true name. I thought about "Destroyer". Sounds clear, right?
Turrets and Guard Posts will fit in these categories. I think that will be a bit odd for Strike and Blitz, but for Archer, Bomber, Specialist and Destroyer, no problem, IMO. (Well, I don't think we'll have many Bomber turrets/posts.) I clearly see the Fortress and HBC in the Destroyer category.
I'm not really satisfied with the numbers (x2, x3, 0.5, 0.75, etc) but as long as they don't get in my way/face, I won't complain. Like I can look them up in an "advanced" tooltip, but I just need to see the class of a unit and remember the arrows in the diagram. Fine.
Just for the sake of discussion.
Where will the Starships be? Each in a category? (Raid in Strike, Leech in Blitz, Plasma in Bombing/Archer, etc) So bombers won't be pure anti-starships anymore. That sounds fine to me.
Where will the Younglings be? All in Strike? All in Blitz/Specialist? Each in a category? (Tigger in Bombing, Weasel in Blitz, Commando in Strike, etc) I think they have a strong connection and should go in the same category. Specialist is my best bet.
Ammo for thematic purpose only is completely fine as long as it keeps a sort of underlying coherency. (I would see something like that: overall, X prefers Y, but there are some exceptions and some exotic ammo: Striker-shell, Archer-missile, Bomber-bomb, Specialist-laser, Destroyer-energy.)
TL;DR:
I like these changes.
Now it's time to refine them.
