I was thinking of abilities that would be cool and one that came to mind is an ability where a hero and a unit he is with can take an extra action.

Anybody else have any cool ability ideas? I'll put some of them up on my blog.

That would be a VERY powerful ability, almost a game-breaker. To be able to move and still make a sustained attack... It would be quite similar to Berserk, so it should be single-use in order to remain balanced.

How about an ability that gives a unit an extra Move action, but it can only be used to move back to a square it has occupied before during that turn. This would allow it to move out of cover, fire, and retreat back to safety. The adversary would need to use Reactive Fire in order to catch it off guard. Not sure whether this should be a limited-use action or not. Maybe call it "Dodge".

I think any of the following would not be over powered and would add an interesting element to the game,

A sabotage skill with a check box, where you could cause an opponent's unit to become flipped, so they cant do anything that turn.

A false orders skill with a check box, with this skill you can select the next enemy unit that has to be activated.

A supply run skill with a check box, with this skill you can "restock" a friendly unit's limited Ammo.

A second wind skill with a check box, this skill allows you to provide another hero a second use of a special skill.

Really like your skills, they seem very organic with the game. Non-combat-related skills are always much more interesting! Specially like the False Orders and Supply Run skills.