KMS's latest skill changes didn't have comments on why these changes happened. But if they did, here's how I would envision them. I won't go over 5th Job skills because this would make my post too long for my taste, or skill error fixes because I see these as bugs that just got fixed.
Part 1: https://orangemushroom.net/2016/12/21/kms-ver-1-2-269-maplestory-beyond-wonder-winter/Hero
Hero's hunting efficiency is a little low, because Raging Blow's attack range is a bit too small, so we have extended the range. We have also adjusted Enhanced Raging Blow, which resulted a slight decrease on its total damage, but having Raging Blow's Extra Strike hyper enabled resulted a slight increase instead.Paladin
In response to Paladin's upcoming 5th Job skill, Blessed Hammer, Elemental Charge's buff is no longer indefinite. However, we don't want to increase the difficulty of this class, so we have changed Blast to no longer consume Elemental Charge stacks and relocated the stats from Blast's buff to High Paladin, effectively turning Blast's buff into a passive effect. We realized that Combat Orders and Elemental Force's damage boosts to earlier jobs' Charge skills were multiplicative, which resulted unequal damages when comparing the four Charge skills. Thus, we have changed Combat Orders and Elemental Force's damage boosts from multiplicative to additive, so that all four Charge skills now deal the same amount of damage. Also, Paladin's hunting efficiency is a little low, because the four Charge skills' attack range is a bit too small, so we have extended the range. Finally, we have increased the success rate boost from Threaten's Opportunity hyper, so that it now makes Threaten guaranteed to inflict the debuff.Dark Knight
Cross Surge's Final Damage boost scales in proportion to your current percentage of your HP. This is a huge problem when fighting against bosses that can hit you for a large percentage of your max HP, especially if there's also a potion cooldown. Thus, we have turned a majority of Cross Surge's Final Damage boost into a passive effect, so that getting hit by a %HP attack will feel much less punishing. Also, Dark Knight's hunting efficiency is pretty low, because Dark Impale's attack range is a bit too small, and Evil Eye Shock is very underwhelming, so we have extended Dark Impale's range and greatly increased Evil Eye Shock's power. Finally, we have removed Lord of Darkness's bonus HP drain from attacking bosses, because it helped Dark Knight stay alive too effectively while fighting bosses.Archmage (F/P)
We decreased Mist Eruption's cast delay to speed up F/P Archmage's bossing pattern.Archmage (I/L)
I/L Archmage is too powerful against an enemy that has 5 Freeze stacks. Thus, Lightning attribute attacks now consume Freeze stacks, but to compensate, Absolute Zero Aura now inflicts a Freeze stack to nearby enemies every few seconds.Bowmaster
We have increased Armor Break's cooldown, because 1 second means all attacks can benefit from Armor Break very effectively, which makes Armor Break too powerful, but also added a cooldown reduction effect, so that Hurricane remains to have a great synergy with Armor Break. We have also increased Hurricane's damage slightly.Night Lord
Showdown will generate too much value gain when compounded with the upcoming Decent Holy Symbol. Thus, we halved the EXP and Drop Rate bonus on both the skill and the Enhance hyper.Thunder Breaker
Primal Bolt's ability to ignore Typhoon's Cooldown and Lightning Buff requirement is far too powerful, so we have added a cooldown to Primal Bolt and decreased its duration, but also changed its damage boost and its DEF Ignore boost to the Lightning Buff into passive effects, so that Thunder Breakers get to keep the damage and DEF Ignore boost active at all times, while the rest of Primal Bolt now has downtime.Phantom
In response to the change on Dark Knight's Cross Surge, we are giving Phantom a lot of Final Damage of his own to not only make up for the change on Cross Surge, but more importantly, to also remove the large disparity between having Cross Surge as your current stolen skill in Impeccable Memory 3 and using a different stolen 3rd Job Explorer skill.Battle Mage
Having Condemnation's character level scaling effect cap at level 180 makes it weak. Thus, we have removed the level cap on boosting its damage, so that its power continues to grow in 5th Job.Wild Hunter
Having Jaguar Skills' character level scaling effect cap at level 180 makes them weak. Thus, we have removed the level cap on boosting their damages, so that their power continues to grow in 5th Job.Mechanic
Mechanic's Rock 'n Shock and Bots 'n Tots are able to have their summon durations be higher than their cooldowns through Robot Mastery and Hyper Skills. Rock 'n Shock and Bots 'n Tots are powerful summon skills, but being able to summon them again immediately after their cooldowns finish makes them too powerful. In our test patch, we originally increased Bots 'n Tots's cooldown and decreased the cooldown reduction from Rock 'n Shock's Cooldown Cutter hyper, however, with Robot Mastery, Bots 'n Tots still last longer than its cooldown, while Mechanics can enable Rock 'n Shock's Persist hyper along with the Cooldown Cutter hyper to counteract the Cooldown Cutter hyper nerf. Thus, we have also decreased Robot Mastery's summon duration boost, because frankly, 70% summon duration increase is way too much.
Part 2: https://orangemushroom.net/2017/01/04/kms-ver-1-2-270-maplestory-beyond-evolve/Paladin
We have made gaining and refreshing Elemental Charge stacks streamlined by no longer requiring an enemy to be attacked by Charge skills.Archmage (I/L)
We realized that Elquines does not inflict Freeze stacks despite being an Ice attribute skill. Thus, all Ice attribute skills now inflict Freeze stacks. We have also made Thunderstorm no longer consume Freeze stacks to avoid unnecessary Freeze stack consumption.Bishop
We added a cooldown to Righteously Indignant, because it felt senseless to be able to toggle it on and off very quickly.Dawn Warrior
We realized that Falling Moon doubles all number of hits, and a fully charged Styx Crossing's base number of hits is 15. Since a skill cannot hit more than 15 times, Styx Crossing at full charge effectively loses 10% Final Damage while having Falling Moon's effects. Thus, we have decreased the base number of hits on Styx Crossing at full charge while also increasing its damage per hit to keep its total damage unchanged, so that Styx Crossing at full charge will benefit from Falling Moon's hit doubling effect.Mechanic
In our previous skill balancing, we forgot to nerf the durations of Rock 'n Shock and Bots 'n Tots. We realized that the downtimes of Bots 'n Tots and Rock 'n Shock that has both the Persist hyper and the Cooldown Cutter hyper active were too small. Thus, we have decreased Bots 'n Tots's duration and the summon duration boost from Rock 'n Shock's Persist hyper.Angelic Buster
Final Contract feels a little too weak, so we have added a new effect to make it a strong skill.