I have played quite a few cRPGs and have seen this implemented on a limited scale. If my memory serves me, in NWN HOTU and NWN2 Cross Roads keep, we were given a chance to partake in a relatively massive battle with all our companions and other NPCs aligned to us against the enemies. I was hoping that we could see more of these set pieces implemented in Project Eternity.
By strategic battles, I mean typically the following:
1. A mid-scale conflict, typically between major factions which will have significant repercussions in gameplay depending on which factions win.
2. The PC and his companions will typically play a pivotal role in the battle. However, since this is a large scale battle, they will only see part of the action depending on what role they want to take.
3. There should be a relatively large amount of fighting between NPCs, probably 30 or more to simulate a mid-scale conflict.
A simple example would be storming an powerful enemy stronghold. Instead of the typical adventure where the PC and his companions unbelievably waltz in and commits whole scale massacre of enemy NPCs without blinking, the quest could take the form of:
1. Gathering allies by convincing various faction leaders to volunteer their men towards storming the enemy stronghold.
2. Depending on the attributes of the PC:
(a) A PC with high leadership and charisma could take strategic leadership of battle by determining the types of tactics and strategy to be used to strom the stronghold;
(b) A PC with thief-like abilities could volunteer to infiltrate the enemy stronghold, scout enemy placements, perform sabotage and open the enemy gates at the appointed time.
(c ) A PC with magic skills could summon immensely powerful spells i.e. meteor storms etc..from afar
(d) A PC fighter could volunteer as the vanguard and charge the enemy gates.
3. During the battle, the PC may have to work closely with his allies to minimize losses rather than going in all gung-ho. He might have to revise his tactics and/or strategy to ensure the enemy leader does not escape. The enemy may have set traps/ambushes/spells of his own and the PC has to turn the tide of battle, so to speak.
One of my pet peeves when playing DA:O was realizing that the PC had no chance to join in the Battle of Ostagar. What a bummer! It would have been fun to wade into battle with my PC and his companions in a free-for-all brawl.