Well, I had mentioned some time ago that I had switched the main ruleset for my Karathor campaign to Sharp Swords & Sinister Spells, and while that is going smoothly, I do often incorporate rules and ideas from Adventurer Conqueror King. But I recently started another ACKS campaign, this time in a more traditional venue, although still (I hope) more archaic and sword-and-sorcery than normal fantasy roleplaying games.
Here is a place where I can post some of the Houserules we've developed for this new campaign.
Saving Throws: We've changed saving throws to D&D 3.x edition Fort/Ref/Will, with all classes starting at +0, but Con modifier affects Fortitude saves, Dex modifier affects Reflex saves, and Wisdom modifier affects Willpower saves. If a class has Str or Con as prime ability: +2 to Fortitude saves. Dexterity: +2 to Reflex saves, or Wisdom/Intelligence/Charisma: +2 to Willpower saves. Also, every 2 levels saving throws increase by 1. This of course means that the DC system is back in, but the normal DC is 10.
To Hit and AC: Again, these reverted to 3.x with it being a positive modifier to a d20 roll vs an AC of 10 + listed AC. This has sped up combat quite a bit since we don't have to subtract Armor Class and just add up to reach the new target AC.
Survivability at Low Levels: Any character with the Adventuring proficiency gains a one-time bonus to maximum hit points of +10. All hitpoints are rolled. This has made some non player characters have more hitpoints as well, but not often, since most non-player characters do not have the Adventuring proficiency.
Fighting Battles: We use a simplified version of the old Games Workshop Warmaster rules. It's less math crunchy but still feels quite epic.
Epic Battles: I've developed my own system for resolving large scale battles quickly. I roll a d4 for each unit, (d6 for elite unit or magic user). Total up the value on both sides. The highest total wins the battle, any 1s rolled will die at the end of the battle. (Player Characters and other special characters of course should have an opportunity to ward off death).
Normal Humans: I could not find any information in the rulebook for 0-level Normal Human statistics, so we've houseruled that they have 1d6 hitpoints, +0 to hit, +0 to saving throws.
Elite Guards/Military: Elite soldiers have an additional +1 to hit, +1 to saving throws, and +1 to morale checks.