Well, the Gangsta manga ends with a mix of closure and ambiguity. Some characters get the resolutions they deserve, but there are still elements that make you think and wonder about the future.
Survival is also a key theme. The 'gangsta' worlds are often dangerous, and when they crossover, it becomes even more so. Characters have to find ways to survive in this new, more complex and dangerous environment. They might have to adapt to new rules, new enemies, and new allies just to stay alive.
Another theme is brotherhood or comradeship within a more 'gang - like' setting. Characters come together not just as a ninja team but as a group with a shared ideology, like a gang. They protect each other and fight for their own beliefs, which might be different from the village's official stance. This can be seen in fanfics where Naruto and his friends form a sort of underground group to support those who are oppressed by the system.
Possibly. Maybe Kohske faced some creative challenges or had other priorities that led to the discontinuation of the series. But there's no official confirmation yet.