Main Difference

Lets start with something basic any Argus player will have to accept from the current revamped argus:

• This is a revamped argus as in the same category as revamped Kaja, Aulus etc i.e a completely different hero but with the same name.
• Previous Argus was an ADC(Attack Damage Carry) for sustained fights with basic attacks as the primary damage. New Argus is skill based damage as primary damage and basic attacks just part of the mechanics/support. If previously it was 70% from basic attacks and 20% from skills now it is 40% from ultimate, 30% from s1,s2 and 30% from basic attacks and passive. Think of previous him as more similar to Zilong and new more similar to Thamuz
• The focus of basic attacks design for the new Argus is to trigger the passive not vice versa. Crit was just chosen as the scaling factor cuz it was already part of his passive and didn't overlap with Aldous or Obsidia. Think of his passive as Obsidia's passive but tied to items instead(Dumb choice but it is what it is). It's also why crit-tickle(as it's called in the sub) damage is limited and even passive damage removed, it's not supposed to be the main focus design wise but just a means, increasing it leads back to ADC side.

Skills

Passive:

• As crit chance increases Argus's ability to recover hp by passive increases. From testing the passive recovery is more chance based but higher effect than actual life steal.
• Since crit damage is low, crit doesn't occur with passive it means crit damage stat can be completely ignored. This is the primary reason for change in playstyle from attack damage.
• However the crit effects can still trigger by passive; Berserker's true damage, Haas' attack speed increase etc do get added to passive slash. So choosing crit chance items is more by the passive than crit damage itself.

S1: No change from earlier, essential engage and escape skill. 1st blink micro stun and slow effect. 2nd blinks is higher damage than S2.

S2:

• Primary move to last hit. Deals high damage along with attack effects activation. This starts off weaker than s1 by base stats but becomes stronger with items. The 40% crit chance (+30% passive) means this is the best crit hit to trigger crit passives. It's best to start with this to guarantee all passives starting off in a fight vs gambling on basic attacks as the starter.
• Very short stun that can interrupt enemy after s1 engage.
• Boost to attack speed. Again as it levels increases boost upto 55% so for the 3 sec after you have highest possibility of triggering passive and dealing most basic attack damage.

S3/Ultimate: DO NOT LET THIS TRIGGER PASSIVELY . Can't stress this enough.

• The passive trigger of this does no damage and does not purify ongoing CC. A VERY VERY DUMB DESIGN. The passive effect encourages players to let it happen for lowest HP use case but the missing effects in passive trigger are actually the game changing ones.
• Inbuilt purify on activation (only you actively using the ult). This removes all ongoing CC effects at the point of activation. They can still be reapplied during the ult after the trigger, unlike purify's immunity
• HIGHEST DAMAGE among available skills, It's double attack stat + 50% more at below 30% HP. Again only if actively triggered. This high damage is secondary reason to skill based damage shift.
• Again dying early game will lock you out of this damage for a while due to cooldown so you can't immediately engage.

Emblem, Talents and Spell

Would suggest between MM and Assassin. The survivability from fighter barely makes a difference.
Assassin gives a bit of mobility and flat pen for early game and squishy heroes.
Marksmen gives attack speed and % pen which benefits more as the game goes on.

Talents:

• Fatal is always best due to passive.
• Master assassin or bargain hunter is go to. Wilderness is playstyle specific. Seasoned hunter is for anyone trying jungler.
• Weakness Finder works well with the passive. War cry will need the ult timed after the bonus starts. Killing spree is playstyle specific.

Spell is sprint for the kiting enemies or petrify to add more CC and buy you time to deal damage.

Items

Boots: Rapid boots or tough boots, no other benefits as much. You can even skip boots if you can make up with other equipment boosts since new Argus has a very high movement speed.

Attack items all the way. Even in defensive only Pauldron, bruteforce make sense passive wise, immortality is end item only if you are already winning.

• First core item has to be between Windtalker or Haas Claws. Wind talker is best for laning and attack speed. Haas gives some survivability if you're getting targetted or for jungle play. Both together aren't worth it.
• Second & third are Berserker and Scythe. Decide the order based on if you need recovery and true damage or slow effect and damage.
• Great dragon spear is the 4th fixed item due to great passive and with the previous 2 crit items will max out passive needs (5% emblem+ 30% passive + 65% items = 100% chance). You can try swapping this with Berserker to see which you prefer. I personally like the berserker passive and crit rate first.
• Other useful items are DHS and Malefic Roar – anti tanky, Halberd – anti heal. Sky or BoD in case low HP enemies keep escaping or end game damage needed.

Exp Lane

Jungle

Gameplay

TRY NOT TO ENGAGE WITHOUT ULT. The new argus changes make him very weak without the ult. He can't sustain enough if you fail to burst down the enemy.

My combos:

Normally

S1 ->S2-> Basic Attacks -> Petrify/sprint if needed -> S1 -> Ult(if needed)

Gank

S2 -> BA -> S1 -> Petrify if needed -> BA/S1 ->Ult (if needed)

Team fight
Takes a little prediction for when to ult based on how low your hp will go on first engage.

S1 -> Burst/ S2 (Depends on reaching 30% HP) ->BA while moving towards safety (sprint/petrify if needed) -> S1 to chase or escape (ideally across a wall)

Important: Argus is incredibly weak against kiting heroes and invisible heroes. If enemies pick cici, lesley etc. I suggest picking another hero instead.

Finally if you're a newly trying to learn Argus then I suggest you wait a bit to see how the devs change it and players adapt.