--Small Changes, because Martials deserve nice things--
Combat Maneuvers Do Not Provoke. In addition, all maneuvers can be attempted in place of an attack. All characters with a BaB of +1 or better count as having all "improved combat maneuver" feats for the purposes of feat qualifications. (note that this does not grant the usual bonuses to those maneuvers. Just the not provoking part. If you want combat maneuver bonuses you'll have to pay for them.)
Exception: Grapple checks to Pin are still standard actions.
Reposition and Bull Rush are for shoving people off cliffs or into campfires. The caveat about not being able to move people into danger with these maneuvers is removed.
Any creature with an Intelligence of 3 or higher receives Combat Expertise as a bonus feat at +1 BaB. Defending yourself with a weapon is instinctive and should not be taxed mechanically. You're already taking a penalty to do it. That's enough of a trade off.
Improved Unarmed Strike is a Martial Weapon Proficiency. Anyone trained in all martial weapons knows how to punch someone.
Dervish Dance is Weapon Specific, but can be used with any Finesse-able weapon. Think of this like Weapon Focus. Pick a weapon when you chose the feat. You get Dex to damage with that weapon.
Proficiency with Exotic Weapons cost a Trait. Because none of them are worth a feat, but they are cool and I like to see them used more often.
Spears of all kinds may be used in one hand by a character proficient in Martial Weapons. Because history.
Characters have a number of Attacks of Opportunity each round equal to the number of attacks granted by their BaB. More skilled martial characters should be better at exploiting combat opportunities. Combat Reflexes adds AoOs equal to a character's Dex modifier to their number of AoOs a round.
Characters have a number of Five Foot Steps each round equal to the number of attacks granted by their BaB. Mobility in combat is important. Nobody likes aborting attacks because they killed their enemy on the first swing.
Reach Weapons do not use the ranged weapon Cover rules. Attacking from behind other people is what polearms are designed to do. A character shouldn't have to invest in archery feats (improved precise shot) in order to use a polearm the way they are designed to be used.
Reach Weapons use the 3.5 Diagonal exception. Normally, pole arms do not threaten on diagonals, unless you are a large creature. Ignoring this little artifact of the grid makes pole arms more functional.
Armor Spikes, Spiked Gauntlets, Bite attacks and other weapons that do not need to be employed in hands allow a character to threaten squares adjacent to them, even if they have attacked with a Reach weapon that round.
Light Weapons can be drawn as a Free action. Treat them as ammunition. If drawing an arrow is a non-action, so is drawing a knife. Pistols count as Light weapons for the purposes of drawing.
No Rage Cycling. Don't even try it.
-- Fun Changes--
Spells don't Fizzle. Anyone that fails a concentration check doesn't simply lose the spell. Instead, the Scroll Mishaps rules will be consulted to see what happens to the magical energy when it is interrupted.
Size Matters: Creatures that are bigger than you might move you if they hit you. Slam or Bludgeoning attacks from a creature one size category larger than their target or any melee attack from a creature two or more size categories larger initiate a Bull Rush as a free action after a successful hit (regardless of damage dealt). This bull rush is not automatically directed by the attacker, and uses the Grenade scatter rules to determine which direction the target is moved. Any result that would indicate the target is moved toward the creature instead moves the target straight back away from them. If you get hit by something four or more times your mass, expect to go flying.
Drawing Objects From Pouches: Any adventurer worth his salt knows that sometimes it's handy to have things like caltrops, tanglefood bags or potions as accessible as possible. As such, bandoleers and pouches are treated exactly like (and cost the same as) Wrist Sheathes or Spring Loaded Wrist Sheathes. A typical belt can hold up to six of them. With a belt and two bandoleers an adventurer could have as many as 20 ready pouches. This rule exists mostly because the system for retrieving small objects is total b$+%#%&~.