Now Arjuna names exactly what he wants to see. The crown. The mace. The discus. Four arms instead of a thousand. He is not asking Krishna to diminish Himself. He is asking for the form that devotees can approach — the Vishnu who stands calm and steady, with the familiar attributes that tradition has lovingly described for centuries.
Think of it this way: a river in flood is magnificent but unapproachable. The same river in its normal course — steady, clear, life-giving — is where people come to drink, to bathe, to sit on the banks and rest. Arjuna has seen the flood. Now he asks for the riverbank.
Notice how Arjuna still addresses Krishna as 'Sahasrabaho' (thousand-armed) and 'Vishvamurte' (universal form) even while asking for the simpler four-armed appearance. He has not forgotten what he saw. He carries the knowledge of the infinite inside him. He simply asks for a form his human heart can bear.