First: In the scan, Saga initially hits Aiolia and sends him into the ground with said move, Aiolia mentions not being able to see it. Then, both clash and "their attacks at the speed of light collided in midair, causing a whirldwind". Saga questions if Aioria knows what he is doing, Aioria says that he'll beat Saga and Shaka stops the fight. Both were evenly matched and Saga didnt even use his attacks. I don't know where you got the "surpassed Saga's speed" part from. He only MATCHED Saga's speed, since before he was slower. Aiolia is no push over, he matched Shaka, afterall.
Second: Yes, in other occasions Saints did surpass a rival without his Cloth, but it is still a important factor and this has been noticed tons of times. Why, in said ocasions, would Shiryu remove his Cloth against Deathmask and Seiya to make it ONLY a factor of cosmo if the armor does NOTHING in a battle? Only if it made a battle unfair and gave a significant advantage.