In the forums, I've noticed a number of people saying that units need more abilities and variety to make both unit creation and tactical battles more fun. This is one suggestion on how to implement this. Obviously, the usefulness of this depends on combat being balanced first, but that's a different topic. This is my idea for something in the future, after combat is worked out.

Idea: Select a training regimen at unit creation (examples below)

A unit could only have 1 training regimen selected, and these regimen would need to be researched. They could require extra training time too. You would still select equipment and such for them as normal. Available training regimen for kingdom and empire could be different. Individual factions could even get their own, special, unique regimen to add to the flavor. Ideas I have include:

1. None (These men have no special training)
Available without research
-30% training time
No abilities 

2. Defender (Stalwart to the end, these men are trained to protect their fellows)
 +100% defense
Ability: Engage (This unit's next melee attack engages and opposing unit. That opposing unit must attack this unit on their next turn and may not move or attack another unit. Use: 1/round, costs movement points)

3. Brute (Chosen from the biggest and the strongest, these men don't know the meaning of 'finesse'.)
+20% attack
+20% hp
-50% combat speed
Ability: Thump (This unit's next attack knocks the opposing unit back 1 space to an unoccupied square. If there are none, the press of bodies in battle negates the effect. Use: 1/round) 

4. Marksman (If they take the time, they will hit a weakness.)
Must use ranged weapon
+20% attack
-50% combat speed
Ability: Aimed shot (This unit's next attack ignores enemy defense and does +50% damage, but this unit looses its next turn. Use: 1/round)

5. Shooter ("Don't aim, just fire.")
Must use ranged weapon
-30% attack
+100% combat speed (or whatever gets them an extra attack)
Ability: Flaming shot (This unit's next attack sets the opponent on fire, causing 5 damage per round and reducing the opponents defense by 50% for 2 rounds. Use: 1/battle) 

6. Savage (Ignoring their own safety, these men throw themselves into battle for the sheer joy of it.)
+50% attack
-50% defense
Ability: Charge (This unit moves 1 space for free, then attacks an enemy in melee. This causes fear in the opponent, reducing their attack by 50% for 2 rounds. Use: 1/battle) 

7. Assassin (They seek only the kill.)
May not use blunt weapons
+50% combat speed
Ability: Deadly Poison (This unit's next attack poisons the enemy, causing 1 damage per creature in the opposing unit for the next 2 rounds. Use: 1/battle)

8. Skirmisher (These men just try to cause as much hurt as possible, without actually endangering themselves.)
-50% attack
+50% combat speed
Ability: Hit and Run (This unit's attacks do not provoke a couterattack. Use: permanent)

One key to this idea, I think, is the fact that a unit can only have 1 training regimen. Thus, the player is forced to choose rather than simply putting the best of everything in a unit. Also, I think it adds some tactical variety if done properly and could encourage combined arms. With my examples above, an army of combined defenders and marksmen would be good because the defenders could keep enemy units off of the markmen when the marksmen lose their turns from their ability. Obviously, this depends on combat being such that one hit kills aren't the norm as is currently the case.

Furthermore, the regimen will need to be worked out so that there aren't godly combinations, like armies that can lock down opponents or unbeatable kiting skirmishers, or something else. Balance is clearly key.

As a side note, I am particularly fond of my assassin's ability, which scales based on the squad size of the opponent unit. Thus, poison is useful against a bunch of men, but not so helpful against that big tough champion or dragon.

That's my idea, what do you think? Would this improve unit design and tactical variety? What other ideas for regimen could be in there? Should units get more than one ability?