Having the ability to deploy a leader after all your troops are deployed. Leader gives you the ability to add +1 to your highest dice roll on attack and defense. Leader does not count as a battalion and therefore has to move whenever the battalions conquer a territory and the leader is used.
If the last battalion is defeated in a territory with a leader is defeated, the leader is defeated. )Could also have the option of getting a second leader using adventure cards)
If you have no leader on the board your leader returns to the board on any of your territories at the end of your your next turn before you draw the territory card.
Strongholds would allow your to provide a better defense against leaders giving a +1 to the highest dice roll on defense. And if a leader was placed in a stronghold the defending player would add +2 to its highest dice roll. Not +1 to each dice.
Strongholds could either be placed in the game like leaders by each player, 1 to each player. Or there could be strongholds placed on the map always the same on each map to be conquered and controlled but when they are conquered by someone else the new person in control owns the stronghold, not destroying it. Strongholds would provide no benefits in attack.