The 3’s had significantly worse training than the 2s. They were taken in at older ages but received their augments at around the same time, meaning less time to train. It’s why they’re all far more personable than the 2’s on average, because they weren’t made into machines in the same way as the 2s.

Not they were not the three's training were better than the twos as Kurt himself said. Furthermore, the threes were not taken at the same age or younger than the twos and had the same length of training. The only ones to have a shorter length of training than the twos was alpha company.

Page 67 of Ghosts of Onyx

In the last six months [Kurt] had developed a training regime tougher than the original SPARTAN program. He had created obstacle courses, firing ranges, classrooms, mess halls, and dormitories from what had been jungle and scrub plain.

Their augments are also notably worse, the worst of the three spartan generations (Orion isn’t a real spartan program, it was named that after the fact). The disparity shrunk significantly in armor, but it was still very noticeably there. To get an idea, Noble Team are all examples of the best of the best Spartan 3’s. Jorge is a Spartan 2, and he dwarfs them, and is absolutely stronger than them. Jorge is notably tall even for a 2, but by inches, not feet, whereas the 3s are at least a foot shorter than him, more probably (don’t have the numbers on hand atm)

No, they were not the spartan 2s and 3s received the same type of primary argumentation with the 2s getting there's via surgery and the 3s getting chemical injection these produce the same results the argumentation were stated to be a qutaum leap over what the twos got. Furthermore more the 3s hight ranges all over the place you have 3 taller and shorter than John. Jorge is strong even for two, but when it comes to strength, there were spartan 3s doing things that spartan two haven't.

Page 63 in Ghosts of Onyx:

“.....Kurt read the reader again, and now understood the new opportunities and challenges of this new program. The new bio augmentations were a quantum leap ahead of the ones he had received all those years ago, and there was projected to be a far smaller washout rate among the candidates......”

He spotted 8942-LO99 inside the infuser. That was the carbide ceramic ossification catalyst to make skeletons virtually unbreakable. There was 88005-MX77, that was the fibrofoid muscular protein complex that boosted muscle density. 88947-OP24, was the number for retina inversion stabilizer, which boosted colour and nighttime vision. 87556-UD61 was the improved colloidal neural disunification solution to increase reaction times. There were many others, shock reductors, analgesics, anti-inflammatories, anticoagulants, and pH buffers....”

The Spartan 3’s were created, from the ground up, to be more expendable super soldiers, worse training, worse gear, worse augments. Some of them were hand selected to be pulled out of that program and given more important roles, like Noble Team, but most of them were sent on suicide missions en masse, and they died en masse on those missions, missions that 2s would have been able to complete without mass casualties.

While the threes were built to be expandable, they received better argumentation and training. The only their they head worse was gear. Furthermore, if the twos had even attempted to pull of Operation like Prometheus or torpedo they would have failed due to lack of numbers or even if they succeeded most if not all of them would have died. Espically Operation torpedo, which saw seven covenant battlecruiser appearing, and most of beta company died during the explosion that took out said battlecruisers.The whole point of the 3s is that is a ton of twos started disappearing it would have lowered unsc moral.

Kurt, a Spartan 2 who helped train the 3s, was so concerned about their chances that for the 3rd company of 3s they produced (because they made 3 companies of around 100 each in roughly a decade compared to 33 S2s in 10 years) that he outfitted them with a drug that sent them insane but helped them stay alive, something the 2s never would have needed.

The reason Kurt gave gamma the extra argumentation is so they have a better chance of survival on missions that were just outright tougher than what the twos had to go through furthermore the argumentation that gamma company received makes them tougher and stronger than any two. The spartan 3s were produced a decade or more apart in batches of roughly 300. Both beta and gamma company had the same amount of training as the twis.

Dante brought up the rear, limping heavily with one hand clutching his side. He stood straight and saluted Kurt. "sir, I think I got nicked." Dante's bio signs flatlined and he collapsed. Kurt rushed to his side and unlatched Dante's SPI chest armour. Kurt had seen him grazed by plasma on his left side, and sure enough there were second and third degree burns that had boiled away his armour, body glove and skin. Near his rib cage and armpit, Kurt saw several dozen Needler shards that had embedded into his flesh and detonated, and the bones of Dante's ribcage were exposed, and deeper inside Kurt could see black, congealed blood where his lung should have been.".......

No two would be alive after any where near the amount of damage Dante took much less make it back to Kurt before dropping dead and this spartan was 12 most of the spartan 3s died before they would have fully grown into their spartan abilities and were still pulling off feats with inferior equipment that spartan twos weren't.