Ok I have a few problems with your rules there.
(Since this is the internet and tone is hard to convey in print imagine I'm saying this with a friendly smile.
Rule one of making rules for anything is every rule must add something be it more depth or greater challenge.
Equipment Rules: Weapons are divided by Weapon Types and Damage Types:
Weapon Types: Balanced (Most swords), Unbalanced (Most club/axe weapons), Reach (Most pole weapons), and Ranged (Bow, gun, and throwing weapons). Generally speaking, balanced weapons outmaneuver unbalanced weapons, unbalanced weapons overpower reach weapons, and reach weapons out-range balanced weapons. Ranged weapons are independent of this combat triangle, and rangers can attack non-ranged enemies in adjacent tiles without fear of reprisal, but are defenseless in melee combat unless they have other weapons. Unarmed attackers are at a disadvantage against any weapon type (except Ranged), but many creatures have natural weapons that more than make up for this discrepancy. A unit may carry multiple weapons, but may usually only use one per turn!
Damage Types: Crushing (e.g. clubs and maces), Slashing (e.g. swords and axes), and Piercing (e.g. spears and bows). After an attacker gets past his opponent's weapon, he goes up against his armor:
Armor Types: Light (e.g. Leather), Medium (e.g. Chain), and Heavy (mostly Plate armor). Fighters with lighter armors can evade attacks better, but heavier armor is more durable and effective at actually preventing the wearer from being hacked into tiny pieces. In addition, light armor is generally more effective against Crushing attacks and less effective against Slashing attacks, medium armor is better against Slashing and worse against Piercing, and Heavy is better against Piercing and worse against Crushing. Unarmored combatants are vulnerable to all three damage types, but are better able to evade, and many creatures have natural armor as good as or better than man-made armor.
Armor Utility: Heavy armor users trade utility for damage resistance- Heavy armor slows down units on the map, preventing them from sneaking or ambushing (unless mounted), most flying mounts and spellcasters are incompatible with it, and all regular armor provides only minimal protection from magic.
These rules add little to the game itself because they only actualy effect one or two players the rest of which are zerg like aliens, self replicating robots and so on.
They attempt to establish a combat system based on one weapon type trumping another in a game where we will likely see laser drills mounted on steel frames go against carapace and claw.
If you bring in rules they need to apply to everything equaly.
And as I orginaly mentioned these rules don't actualy add much, why such damage type matter? why should armour type matter?
Additionaly they aren't very clear: how according to these rules does a combat between (4x Unbalanced+ 4x Balanced) versus (4x Reach+ 4xBalanced) get resolved?
--Cavalry: Ground-based mounted units may move an additional square on relatively flat, open terrain, but move one square less on rough terrain like forests, and take two turns to pass over broken terrain such as mountains.
However this rule does add something.
First since you leave it up to the player to decide what units of their's is cavalry it can apply to everyone and second it changes the way the game is played and how units behave, something which weapon trump triangles don't really do.
Additionally, mounted units tend to be more vulnerable to piercing attacks.
Why?
In order for the cavalry rule to work it has to be able to be applied to anything cavalry like, which could be a jeep or any kind of creature that is large and moves fast.
Addendum to Flying Units rule: Flying units are highly vulnerable to Ranged weapons. Try to keep them away from archers and gunners!
And this is straight from every fantasy tactical game I've ever played.
The reason it's done is to make flying units balanced as the majority of fantasy units are melee combat only.
In this game I don't imagine this will be the case (far from it in fact) so this will be an unessicary nerf that has little consquence on the game other than being another little fact to remember.
NOTE: Firstly, these are all general guidelines that are open to expansion, and all of them have will have exceptions! Secondly, weapon quality matters, and the wielder even more so- a tribesman with a spear's still likely to get ripped open by an armored and/or experienced swordsman. Thirdly, this framework mostly applies to ancient/medieval warriors- bullets are probably [Rng/Crsh], and lasers and force-swords should probably tie into magic rules.
Rules should be as polymorphorous as possible.
It's easier to expand polymorphorous rules, the players don't need to know lists of exceptions to use them and they tend to cover things neatly.
Your rules here only covers conventional melee weaponry and still give no word on how combat should be resolved.
As an example here's my alternative to your rules:
Units have attack and defense.
The units attack score covers unit training, equipment and anything that contributes to it's ability to directly kill it's enemy.
The defense score covers anything that contributes to it's ability to survive damage.
When combat is started the player that intiated the combat rolls a d6 for every six units in the combat (less then six roll one d3) and compares the total attack of the units present in the combat + the total result against the total defense of the enemy + a d6 for every six units(less then six roll one d3).
The amount the attack is overby is the number of units the defender loses (lowest defense units are lost first).
The defender then gets a chance to attack.
This continues until one side is dead or decides to retreat.
Combat can only happen between two forces occupying the same square.
It's much simpler, covers all the bases, is very easy to expand upon and fits better with what we already have.
In case your wondering I design table top systems and board games as a hobby which doesn't nessicarly make me any good at it but it means I spend a good deal of time thinking about and I am, as I fear I may have just demonstrated, quite enuthastic on the subject.
This is meant as a friendly critism and if you want to see how not to do a simple clear gaming system you should see my Firestar game.
And two last things: the consesnous seems to be that this is a sci fi setting and finialy if this post seems weird it's because it's a quarter past two in the mourning here and my brain is slowly shutting off.