I think the current system of a single tactical action resource (combat speed/action points) is workable, it just needs tweaked by introducing variable costs and percent modifiers to those costs based on the previously existing stats. This is a restatement of the ideas I presented in post #84, with emphasis on tweaking the current system and how those tweaks effect the problems presented.
Tweaks to current system:
All units with the ability to move (so anything besides a watch tower/stationary golem) should have a minimum combat speed of 2, since that's the base cost of movement into a regular square. Units with fewer than the exact AP necessary to complete an action can't take that action.
Weapons have different AP costs associated with them. This provides interesting choices of weapon damage versus the number of times you can swing it in combat versus equipping every character with a single best weapon. It allows you to make ranged weapons slower to balance them instead of giving them less damage.
Spells need to have different AP costs associated with them. This provides a badly-needed way to differentiate between the spells of different schools. Right now, Throw Boulder, Icebolt, Firebolt and Lightning Strike are all essentially the same spell. If they have different AP costs, you can have a low-level earth spell that takes longer to cast, but does more damage, a fire spell that casts quickly for high damage but higher mana, etc.
The AP cost of an action should be modified by the relevant stat. So, magic AP cost is modified by intelligence, blunt weapon and ranged weapon AP cost is modified by strength, edged weapon AP cost is modified by dexterity, and movement cost is modifier by movement speed (not combat speed).
AP costs for everything should be modified by morale, essence, and armor type. Armor impacting all AP costs, like different weapon AP costs, gives the player interesting choices between heavily armored, but slow, units versus lightly armored faster units, rather than everyone just rushing to the highest armor possible on all units. It also makes magical armor that is lighter, rather than stronger, worthwhile, and creates an advantage of weightless defensive spells like mage armor.
Lose the restriction on moving, then attacking, because it's an artificial restriction that won't be needed with the above balance suggestions. Hit and fade attacks should be an option.
Problems these tweaks address:
1. The Sauron/Calvary Problem: These changes allow you to create both Sauron and cavalry within the current system. Sauron has a high combat speed with many action points to spend on either movement or attacking, so he can wipe out multiple ordinary units in a single turn. In addition, Sauron has essence, which decreases the cost to him of moving or attacking, no matter what square type he's moving through or what weapon he's using.
The calvary, on the other had, has a normal number of action points and a normal combat speed, so they can only do as many attacks as a non-mounted unit. Their mounts, though, increase their movement speed, which in turn decreases the cost of movement for them, so they can move farther in their turn.
For example:
Sauron has a combat speed of 4.0. Because of his essence advantage, attacks with his FrogBlade cost 0.5 AP and movement costs him 1.5 AP. So, he can move 2 squares without attacking (unlike the current system, I propose you have to be able to pay the whole cost), or attack 8 times, or some combination of the above.
Cavalry has a combat speed of 2.0. They attack with their long-swords for a cost of 1.0 AP per attack, but because of their fast movemeent speed, movement also only costs them 1.0 AP. So the cavalry can move 2 squares (just as far as Sauron), but can only attack twice if they don't move.
2. The non-caster sovereign Problem: Many have raised the issue that non-caster sovereigns just don't have a compelling reason to hold onto their essence. The proposed modifications change that. Say Sauron in the example above uses half his essence imbuing land, heroes, or just losing it to tricksy hobbitses in Texas Hold'em. The loss of half his essence modifier makes his AP costs go up, so now movement costs him 1.8 AP, the FrogBlade 0.6 AP. He can still move just as far, but can only attack 6 times per turn (a 25% loss in damage), so he feels the loss of his essence in combat.
3. The paucity of important decisions Problem: Right now there are not emogh real trade-offs in unit design other than cost. You always want to build the fastest, highest-damage, strongest-armor, longest-attack range unit you can afford. It is unlike GalCiv, where hull space forced you to make trade-offs between offense, defense and range in unit design. By giving weapons different AP costs and having armor modify those costs, the player can now make interesting choices about lightly-armored rangers, light cavalry versus heavily armored footmen and heavily armored knights. Armor currently subtracts a fixed number from combat speed, which serves a similar purpose, but matters less the faster a unit's combat speed is. The current way weapons add to combat speed gives you a strange situation which a mage might be able to cast more spells per turn because of what kind of sword he's holding (which, I suppose, if nothing else changes, creates an interesting opportunity to create mage weapons which do no damage but simply add to a mage's combat speed).
I've already mentioned that the spells for the various magic schools feel like reskinned copies, particularly at the lower levels. Adding AP cost to spells allows another way to differentiate between the magic schools. Earth magic should feel slow, cheap (mana cost) and powerful; Air fast, cheap and weak; Fire fast, expensive and powerful; water slow, moderate cost, moderate power.
Anyway, I hope these ideas are useful in some way, even if it's just furthering the conversation.