Celebrim
Legend
The secret is noting that spells are the real power of the spellcasting classes, and they are only as good as the spells that they have. The reason that martial classes are weak is that what they are good at - feats and skills - are weak.
Skills need meaningful active uses in combat and otherwise. Skills are far too weak. They feel like they are envisioned solely as means obtain passage through a DM selected obstacle. You can use Open Locks if there is a locked door. You can use Knowledge if there is some McGuffin that can yield clues. You can use Balance if there is some ice on the floor, or Decipher Script to get clues from the ancient runes. But very little of it feels like something you can plan for and depend on, which is very much not like a spell.
Tumble is an example of an existing skill with meaningful active uses. Use Magical Device is another. There needs to be more skills that have an impact on combat either by expanding the uses of existing skills or creating new skills. As level increases, these skills need to have an increasing chance of impacting combat without requiring an action, either by 'dispelling' debuffs or by inflicting debuffs. It wouldn't hurt if Heal could be used to do some minimal but useful real healing. Expanding the skill system would require expanding the number of skill points available to non-casters, as skills have to be seen as something of a class ability and access to skills is like getting access to spells.
Martial classes need to go increasingly non-linear at high levels. If 2 bonus feats every 3 levels is good at low levels, then by the upper levels they need to be gaining at least 1 feat or class ability per level. And feats that are 3 or more feats deep into a chain and/or available at high levels have to just rock and have to address not just increasing damage but the ability to deal with statuses and obstacles. I disliked most of the existing 'Tactical' feats, but the core idea of, 'This feat makes you better not at 1 thing, but at 3 different things', is ideal for higher level feats and is generally better design than make a 3 feat tree where each feat gives you a small separate bonus. Push the whole tree down into a single feat unless the bonuses gained are pretty huge.
If you have the feats, expanded combat options, and skills in place, there is really only relatively small changes to the classes themselves that are needed. Under my rules the big changes aren't necessarily to the classes themselves.
1) Fighter = gains 5 more bonus feats, a couple more skill points, better skill selection and a few minor class abilities.
2) Rogue = gains resistance to ranged touch attacks, gains essentially 2 more bonus feats and a couple more skill points.
3) Barbarian = gains some flexibility in creating its class skill list, loses the alignment restriction, gains literacy, gains some selectable resistances.
Frankly, that's piddly, and it points out the big problem you usually see with people trying to fix the martial classes. It's not the martial classes that are really the problem.
Yes. Without making martial classes explicitly magical, there is only so much you can do to buff them up. Your martial superhero might can leap small buildings, run faster than a horse, crash through brick walls, survive collosiions with freight trains, and cleave things left right and forewards but he's still going to be limited compared to someone who can outright fly, teleport, raise walls of force, summon aid of every sort, divine hidden secrets, and raise the dead. You probably never can fully close that gap, but there is quite a bit you can do to turn down the power of a caster while still leaving them very very useful. Once you do that, the general durability and damage dealing power of the martial classes can shine a bit more.
One example of what I do is nerf 'save or lose' by no longer adding the spell level to the DC of the save, and being careful about how much I allow DC to be bumped up. Similarly, I avoid adding 1/2 HD to the DC of saving versus as monsters attack. This returns things to the 1e standard where at higher levels, most foes only failed saves on 1's or maybe 2's and somewhat elimenates the dependency for absolute immunities like Mind Blank, Death Ward, Freedom of Action, and Hero's Feast without which a martial class is normally helpless at higher levels.
It's also important to give the spell list a quick run through and make sure that you don't use broken versions of things like Haste or Heal from 3e or broken versions of things like (among other things) Blasphemy, Alter Self, Evard's Black Tentacles and Ray of Enfeeblement from 3.5e. And Polymorph from both (see 1e for a better example of how to do Polymorph well). Alot of spells were bumped up in power in 3.5 for no good reason. Similarly, you have to watch out for absolutes like Wall of Force and Forcecage. Anything that grants immunity is suspect.
