Old skills which has to be kept!!!

The most important skills from 3rd prof which should be kept!!!
(if you learned new 4th class skills and deleted following skills, you can delete your character and start another from scratch. or you need to level up to some level, where new skills are better):

Soultaker: Day of Doom
Archmage, Mystic Muse: Cancellation (old cancels cannot cancel new buffs, but they can cancel noblesse blessing/item skill: reflect damage/freezing skin/etc etc etc)
Dark Avenger: Reflect Damage + Shield Deflect Magic (until 99 lvl, when Spike Shield can be enchanted on +time, constant 20% reflect are much better, than periodic 50% reflect)
Cardinal, Eva's Saint, Shillien Saint: Robe Mastery
Shillien Saint: Prophecy of Wind (magic critical damage and HP, Drum Melody increases only magic critical chance and MP)
Dominator: Victory of Paagrio (magic critical damage)
Soul Hound: Steal Divinity (same as cancellation)

Useful skills (you can learn new skills, but these old skills are usually better) (list may be incomplete)

Soul Hound: Quick Recovery (trade of 13% cast speed for 20% skills reuse)
Doombringer: Rush Impact
Doomcryer: Chant of Victory
Dominator: Flames of Invincibility
Eva's Saint: Prophecy of Water
Cardinal: Resurrection, Mass Resurrection (new versions have fixed reuse 30 seconds and 600 seconds, but % of resurrection are much better, you will lose A LOT (i mean A LOT) of expereince after dying on high-levels. new Mass Resurrection also targets only party members instead of clan members)
Eva's Saint, Shillien Saint: Resurrection
Adventurer: Dash, Lure
Arcana Lord/Elemental Master/Spectral Master: Summon Smart Cubic (until ~90-95 lvl new cubic lacks cleanse and hardly do anything)

Useful skills (you can learn new skills, but these old skills can be better in some situations) (list may be incomplete)

Dreadnought: Provoke, Thrill Fight
Arcana Lord/Elemental Master/Spectral Master: Transfer Pain (70%-75% of transfer on new skill maybe too much, you cant heal summon that efficiently)
Hierophant: Mystic Immunity (Battle Rhapsody are much better for pvp, but Mystic Immunity combined with Angel’s Touch can do wonders on olympiad)
Sword Muse/Spectral Dancer - All Rhytm combo songs. its highly experimental, but basically you lose 1-2 berserkers and gain somewhat of combined mage+knight's harmony.
Wind Rider: Dodge
Moonlight Sentinel: Rapid Fire
Ghost Hunter: Counterattack
Archmage/Mystic Muse/Storm Screamer: Arcane Power
Storm Screamer: Empowering Echo
Titan: Frenzy
Grand Khavatary: Force Rage

Some information about the archer (saggi) ?

this is a really helpful information as i am just about to level up and i was hoping to delete old skill to welcome new skill in and i reckon without this information i would have deleted skill that would have later on been much more helpful to me, i guess it is really best to learn from other people's experience as i know you guys know more than a beginner like me thank you so much and this info is much appreciated