One idea could be exploring Peacemaker's backstory further. Maybe his childhood and how it shaped his current self. Another could be a crossover with other DC characters, like how he'd interact with Harley Quinn.
Overall, Peacemaker is reasonably faithful to the comics. Some details might be tweaked for the screen adaptation, but the core elements remain intact. The characters and their arcs are largely consistent.
It depends on your perspective. Peacemaker has complex traits and actions. While he may do things that seem heroic in some situations, his methods and intentions can be questionable in others.
Definitely. Peacemaker is an actual comic. It offers unique story arcs and character developments that have captured the interest of many comic enthusiasts.