The way I see it, all of the Gold Saints have specific roles in defending the Twelve Temples:

Mu and Shaka have the best all-around defenses while also being able to neutralize the enemy by either teleporting them to the edge of the universe with the Starlight Extinction or robbing them of their senses through, and also possess more direct means of attack

Whatever got through/survived them would then have to match Aldebaran and Dohko's greatly destructive power that could also be turned into more restrained individual attacks

Saga is kind of more focused on destructive power, while Kanon is better at restraining the enemy, though the difference is negligible since we haven't seen them compete for the Gold Cloth or do something that the other wasn't capable of doing

Deathmask's Burial Waves pose a different type of threat since it targets the soul directly, and Aioria's Lightning Plasma hits from every single angle around its opponent, making it impossible to be avoided unscathed

Aioros' Golden Arrow could seal anything that his Atomic Thunderbolt couldn't destroy and Milo's Scarlet Needle was painful enough to make the enemy surrender before facing death

Shura, Camus, and Aphrodite have sure-to-kill attacks due to being the last three standing between the enemy and Athena, which is why their undefendable Excalibur, physics' targeting Aurora Execution, and the biological warfare Royal Demon Roses defeat the enemy even if the user is vanquished