There are five changes which I clearly identify as key to putting the fighter back in the forefront of adventure.
- Limit hit points. Characters have the same amount of hit points for life.
- Separate to hit and to damage roll. Give the character a separate to hit roll on which all combat skills are applied.
- Penalize heavy weapon and armor usage. The heavier the character the slower the attack.
- Change the initiative roll. It's a skill check now.
- Add group skills. A great deal many fighter skills are fighter centric, let his skills affect the group.
Limit hit points
Rising hit points is a common game design concept. As characters level up they gain more hit points. The idea being that these hit points represent a degree of skill and luck. Unfortunately to maintain encounter balance as characters rise in level so do the monsters rise in hit points. This creates a requirement for ever rising spell powers too. After all if the magic user is going to be a relevant character in 6th level encounters the spells need to do more than the 1d6 magic arrows did at 1st level. So magic user spell power rises because monster hit point rises.
In Era characters have the same hit points for life.
Separate to hit and to damage roll
Separating the to hit and to damage roll means having a roll to determine if the target is hit and another one to determine if the damage is sufficient to penetrate the armor. Doing this gives a clear die roll to which the skill bonuses are applied. Skill is not something abstracted into hit points, it is clearly applied on the to hit roll and also in the dodge and parry rolls. The character either hits or misses. If it hits it might pass the armor and damage the character. Nonetheless there is no ambiguity as to what happened. Nothing like a hit that does 10 hit points of damage, but actually means the character turned the attack into a glancing blow.
Having this separate skill allows the game mechanics to add all skill bonuses to the to hit roll in the form of skill bonuses and not as extra damage. This once again reduces the classic hit point escalation that eventually leads to meaner monsters and more powerful magic.
You might guess by now that the fighter class will be the one enjoying the most bonuses when it comes to hit rolls. More so, since the magic user spells are weaker now (see fixed hit points above). It's harder for the magic user to hit and do damage than it is for the fighter.
Penalize heavy weapon and armor use
Most games don't take armor and weapon weight too seriously. Yes, some do have a penalty or a cap on dexterity bonuses. But that only matters if you have high dexterity to cap! By putting a fatigue based mechanism into place that grants more attacks to faster weapons and lighter armor the game benefits the lightly equipped character.
Initially you might think this is counter productive to the fighter, but take a closer look. Who's going to have the high strength, dexterity and constitution attributes to carry all that armor? Well the fighter of course! So the character best fit to use heavy armor is the fighter. He'll be really good in armor while the other classes not so much, and he'll be even better out of it because he'll be lighter and more agile.
So stripping the armor and heavy weapons from the fighter makes the character focus on skills to prevent getting hit. This promotes a fighter that is good without armor and excellent with it.
Change the initiative roll
Last game I changed the initiative roll from the classic 1d6 or 1d10 and lowest goes first to a skill check. Characters must succeed in their skill check to maintain their coolness in combat. Guess who has that the highest? The fighter. By moving away from a random initiative that anyone can win at, to one in which the fighter is more skilled at, I'm giving the fighter an advantage over the less battled hardened fellow party members.
Add group skills
Instead of adding more skills that grant more attacks per round, more damage per attack and more and more weapons, I'm adding group skills. The fighters natural coolness in combat makes the class a natural leader for the party. Why not exploit this as leadership and command skills which help make the party a better combat unit. A bit like the cleric's bless spell, but with balls.