HISTORIC

Medieval armies marched in rank and file for a simple reason. In a world without radios, accurate maps, and global positioning systems, marching in one organized group was the only way to make sure every soldier made it to the battlefield and followed orders once there. Amid the din of battle, soldiers have to be able to hear the shouted orders of their commanders, so they couldn’t spread out very much.
Because historical armies marched in rows and columns, obtaining cover and concealment is next to impossible. Battlefields are often large plains, because only in such places can each general stay in contact with the army’s units. Camouflage isn’t an
issue, so armies wear colorful uniforms and carry standards identifying their unit to make it easy to tell friend from foe. Generals send runners with new orders to units, and because the units are easy to identify and reach, those orders are likely to reach subordinate commanders. Catapults are the only artillery weapons, and they’re rare sights except during castle sieges. Horse-mounted cavalry was a powerful force on the battlefield, because it could reach the critical ground in a battle quickly. The high walls and arrow slits of a castle provide excellent protect for the defending army; a siege against a well supplied stronghold can go on for years.
The biggest advantage to historical warfare is that it feels properly epic, with row after row of grim-faced soldiers marching in lockstep toward the enemy. Castles and knights are central to battles in the medieval tradition, and unit tactics respect the difficulties of communication, navigation, and command.
Historical warfare doesn’t always interact well with magic or monsters. A single fireball can devastate large groups of marching troops, and high-CR monsters can wade through column after column of foot soldiers with impunity. Traditional castles are hard to defend against enemies who can fly or teleport.
If you want your D&D battles to include a strong historical element, use feats such as Hold the Line and Phalanx Fighting to bolster the effectiveness of soldiers in formation. Have soldiers prepare for spells that affect a large area by thinning out their ranks with the disperse maneuver. Make flying creatures and monsters with magical abilities rare on the battlefield.

MODERN

t’s not hard to imagine a different means of waging war. By replacing technology with magic and monsters, D&D armies can employ tactics and techniques that wouldn’t be out of place on the 21st-century battlefi eld. A band of elf rangers might hug the tree line on the edge of the forest, seeking concealment and cover among the trees. Every squad of soldiers might have a cleric to act as medic, a rogue sniper, and a sorcerer to provide fire support with lightning bolts. Dragons can provide combat air patrols. Teleporting monsters function as paratroopers, suddenly appearing behind enemy lines or seizing important objectives. Whispering wind and message spells can provide instantaneous communication between battlefield commanders.
Powerful monsters and magic rule the modern-inspired battlefield. Giants and other big monsters are the D&D equivalent of tanks: fast, frightening, and built to absorb a lot of punishment. Low-level foot soldiers tend to dig in, relying on cover and concealment to protect them. Foot soldiers also disperse more widely and use ranged attacks more often; even fifty 1st-level warriors can’t bring down a giant in melee, but they can wear it down with arrows, and if they’re spread out, the giant won’t kill more than a few of them each round.
Castles and other strongholds are harder to defend, especially against an enemy who can fly, teleport, or use magic to turn your fortress walls to mud. Thus, underground strongholds (dungeons, in other words) are popular, because they can’t be attacked from above, and enemies who don’t know their layouts can’t teleport into them.
Aerial Recon: Giant eagles have a Spot modifier of +15, so they make excellent scouts, circling the battlefield at great altitude to watch troop movements. A giant eagle can fly higher than 300 feet still and have a better than even chance of spotting a Huge creature (or 10 Medium creatures moving as a unit). Unless the creatures on the ground are specifically scanning the sky for the giant eagle, it takes a DC 26 Spot check to notice the eagle at that height.
Clerical Medics: For half the price of a suit of full plate armor, a 1st-level cleric can be equipped with a fully charged wand of cure light wounds. Such a cleric typically prepares bless (to use before battle) and entropic shield and sanctuary to keep him safe while he runs, wand in hand, from wounded soldier to wounded soldier.
Fire Support: A squad of infantry often includes one or more spellcasters who can bring arcane firepower to bear on the battle. A 4th-level sorcerer, for example, can cast four scorching ray spells and have plenty of mage armor and shield spells in reserve to protect himself. Equip him with a wand of magic missile (750 gp) and three scrolls of fireball (375 gp each), and you have the sorcerous equivalent of a machine gun and rocket launcher—and it costs less to equip the sorcerer than a typical knight.
Specialized Troops: Sahuagin make effective marines; they can establish a beachhead in enemy territory by swimming ashore at night and slaughtering the coastal guard, and they can swarm a ship at anchor, attacking the crew or simply bull rushing them off the deck to be eaten by waiting sharks. Barghests can use dimension door once per day to instantly move up to 640 feet and are effective trackers, so they can function as paratroopers of a sort and seize key objectives in advance of the main army.
Blitzkrieg: With a speed of 50 feet, winter wolves are as fast as all but the fastest horses. They have a strong melee attack and a breath weapon that’s effective against massed troops, so winter wolves can often punch a hole in a defensive line that slower troops can then exploit.
Behind Enemy Lines: A team of 4th-level bards can easily slip behind enemy lines by using invisibility or alter self (perhaps in conjunction with Bluff, Disguise, and Diplomacy checks). Once in the enemy rear, they can use detect thoughts or suggestion to gather intelligence and an animal messenger spell to report what they have learned back to headquarters.


Source: DnD 3.5 Complete Warrior

Man sieht also: Es kommt vor allem darauf an, wie stark man das Fantasy-Element ausbreitet. Je mehr Fantasy-Aspekte in die Schlacht eingebracht werden, desto schwieriger wird eine historische Schlachtordnung.

Nun, wie gesagt, die Ausmaße des Fantasy-Aspekts machen's aus. Natürlich ist nicht jeder zweiter Mensch ein Magier/Hexenmeister, und Rüstungen schränken die Bewegungsmöglichkeiten ein und somit die genauigkeit beim Zaubern mit Gestenkomponenten. Aber ein Zauberstab, in dem mehrere Ladungen des selben Zaubers gespeichert sind, oder eine Schriftrolle, von der man einen Zauber einmal ablesen kann, sind gute Hilfsmittel, selbst, wenn sie nur Menschen mit Magie benutzt werden können. Es ermöglicht eine viel häufigere Anwendung der Zauber.
Was die Möglichkeiten der Konter gegen z.B. Drachen angeht: Wir können heute auch Flugzeuge und Helis mit FLAKs oder FlaRaks abschießen. Na und? Trotzdem kämpfen wir nicht mehr in Großen Heeren, die aufeinander zustapfen. Nur weil beide Seiten mit Raketenwerferähnlichen Magiern bestückt sind, sind diese nicht weniger effektiv.
Aber natürlich hast du auch irgendwo Recht. Wenn es sehr wenige Magier gibt, ist es schwierig, einen Trupp aus vier Kämpfern, einem Scharfschützen mit Armbrust und einem MG-Magier als Standard-Formation zu nutzen. Je rarer die Magier sind, desto seltener sollten sie nahe der Front gefunden werden. Sie könnten in solchen Fällen viel besser zur Kommunikation dienen, als Ersatz der Radio-Technik, und so die Heere beisammenhalten, während sie nur in Schlachten die gesicherten Gebiete verlassen.