I think that there might be a cliffhanger at the end possibly suggesting there will be more DC to come but made by someone else. With a property as popular as DC it could go on forever and eventually fizzle out in the far future after everyone grows tired of waiting for the real ending. Which may not be in our lifetimes. DC like Pokemon will be milked for all it is worth till the well runs dry. It is inevitable that all good things like DC will end, just not any time soon.
Eventually the hero/main character wins the day but not unscathed mentally or physically. They may need some serious therapy at the end.
When I saw one of th DC movies a thought accord to me that Ai and Conan may have to grow up naturally instead of using the antidote. Going with the theroy that Ai an Conan may have grow naturally instead of using an antidote, the ending may be like that dream Conan had, I think it was in one the specials, where He, Mitch, Ai, Ginta, and Ayumi are teenagers,I think in high school, and ran is probably still clueless about Conan being Kudo.