Let’s start off with the easiest and most basic class: the fighter. The general stereotype about 3.x is that casters win the game and fighters are worthless; while it’s true they’re one of the weakest classes in the game, they have some strong advantages, and smart optimization/equipment choices/caster support makes fighters a viable combat machine.
The “Fighting Man” is one of the three oldest classes, dating back to the original Little Brown Books (oD&D). Fighters have generally had the best attack progression, high health, and the ability to use the best equipment. AD&D fighters were the only classes who could gain weapon specialization, offering bonuses to hit and to damage. 2e AD&D continued weapon spec. by adding in weapon group proficiencies, and added in the core four fighting styles: single weapon, dual weapons, sword-and-board, and two-handed-weapon. 2nd Edition also contained a lengthy list of example fighters:
Hercules, Perseus, Hiawatha, Beowulf, Siegfried (Sigurd), Cúchulainn, Little John, Tristan, and Sindbad… El Cid, Hannibal, Alexander the Great, Charlemagne, Spartacus, Richard the Lionhearted, and Belisarius.
It’s also worth noting that at higher levels, fighters got castles filled with troops and followers. AD&D fighters were awesome like that.
Fighters got a leg up in the 3.o rules. The addition of Feats meant that fighters could now be easily customized, and multiple fighters in a party could do very different things. The fighter retained all the basic abilities, such as the d10 hit die and fast BAB, but gained the worst skills per level of all classes. (Painfully so.) The idea to customize each fighter with dozens of feats and fighting styles/maneuvers meant that fighters had a lot more to do than roll to hit, roll damage. Fighters saw no major changes in the 3.5 revisions.
Pathfinder’s changes were notable: it increased feat acquisition, furthering customization, added “weapon group specialization” back into the game, gave a bonus to Will saves against fear, and a reduction in armor penalties. However, despite their attempts to make it viable from levels 1 to 20, its capstone ability is lacking. 4th Edition codified the fighter as a martial Defender, using its solid defensive abilities to protect other characters. Their focus is on damage output and mobility control, while retaining their traditional high health and attack rate.
Strength to hit and do bonus damage, Dexterity for ranged combat and a better AC, and Constitution for health. In 3.x and Pathfinder, it can be a good idea to bump Intelligence for extra skill points, and Wisdom to make up for that pitiful Will save.
Role within the party
The most obvious one: the frontline combatant, the warrior, the guy standing in front of the artillery (magic-user) and his healing support (cleric). Fighters have been defined as anything from bodyguards to bandits to soldiers, and everything in between. In actuality, they’re close to defensive lineman in football: they get into the midst of the scuffle, and using their strength and prowess, keep the enemy line from attacking the more vulnerable members farther back.
Fighters are an interesting role to play. Their main build in 3.x looks like a slugger from their damage output potential, but that’s only half of the role. Given their higher AC and health, fighters are generally good targets for the GM to swing at, since they’re less fragile than the other party members. Thus the fighter ties down the enemy and makes himself a target, allowing the other party members to set up for spellcasting or sneak attacks. The fighter has to survive a lot of attacks, but also has potent offensive capabilities, getting more attacks (and thus, more hits, and more damage) than anyone else.
Fighters have huge advantages, particularly at lower levels. They have the most hit points per class (save barbarians in newer editions) because of their d10 hit die. They can use all the armor, all the weapons, and can specialize quite easily in whatever equipment they choose. They have the best attack progression, get the most attacks per round, and with their huge arsenal of feats, are highly customizable combat powerhouses.
However, their disadvantages are numerous. They are legendary for having terrible Will saves, and are easily dominated or confused by enemies with spells or spell-likes. Until Pathfinder added in Bravery, fighters were also terrible cowards who’d fail saves against fear. They also have the amount of skill points imaginable; the fighter has roughly two skills he’ll shine at, probably Climb and Swim. And having all that heavy armor makes them sluggish on the battlefield: plate is great, but reduced speed and encumbrance aren’t. Pathfinder’s Armor Training is a major help in this area.
As they progress in levels, it becomes harder for a fighter to stay competitive; even their bundle of feats and abilities pales compared to a well-built spellcaster. In fact, fighters at all levels are reliant on the party casters: buffs and terrain-negating spells make combat much easier. The fighter is still a damage powerhouse due to its great BAB and number of attacks, but is outshone on the damage-dealing front by a rogue pulling off multiple sneak attacks. The sheer level of customization available from all those feats is impressive, but the player has to be strict in their choices to outshine the advantages of a paladin, ranger, or barbarian via the bonus feats.
Fighters have always been a second-stringer in high-level D&D, moreso in 3.x. Rogues do better damage, Clerics and Wizards dominate the battlefield through their spells. That said, the fighter can still be a decent class, pending proper building and support from the party’s casters. The fact that it’s so reliant on optimization and caster support point out that the class needs some modifications, but fighters are still very useful, particularly in the “sweet spot” of low-mid level combat.