I think instead of all this shooting at one another, Lucas could've just clarified his intentions by cutting in a quick insert shot of Greedo raising his blaster or about to squeeze the trigger. Just something. The scene just feels fairly devoid of tension. How the heck is Han NOT supposed to come off as a cold blooded killer if Greedo just waves around a blaster throughout the scene? Despite his dialogue, he just doesn't LOOK like he's about to shoot anyone.