I've always thought a good introduction for Aquaman in a film would be:
Begin with an establishing shot of an oil rig in the middle of the ocean. We then see an explosion protrude from the side of the structure. A tracking shot of would reveal people running in terror from what is coming. People are jumping into evacuation vehicles. We see green, shark finned boots walk by the screen, cut to some PMC soldiers firing assault rifles at the assailant, screaming that he is just standing there taking the bullets. Apart from one cut to the assailant's eyes and forehead to show one bullet just about break his skin he still isn't seen yet, only his boots visible.
The end of a golden trident slams into the floor, triggering a deafening crack of thunder. It begins to rain. The PMC disperses and flees the scene. From a longshot of the oil rig structure we see a figure scaling the structure.
At the top of the structure, we see the figure from behind, it's a man, orange tinted gold armour and long unkempt blonde hair. He hoists the trident into the air and from the depths a vicious Kraken like monster wraps its tentacles reaches throughout the structure, tearing down the concrete abomination. The man is also pulled into the depths.
But he arises again, finally giving the audience their first full view of him, the scale mail, the green gloves, and the golden belt adorned with the symbol for Atlantis, or to the audience, its second meaning- Aquaman.
TL;DR, Aquaman can be awesome, at least to me, he can.