Four releases in, I feel like this might become a strong series, but as it is, I feel like it has an identity crisis that it hasn't yet put to the test. It certainly doesn't feel like a short series, but one that is putting down roots for the long haul.
I'm not really following the releases right now, but Duranki was always presented as a series that would be long-running as far as I know. It seems some people have been assuming it would be short, like Gigantomakhia, but that's not what its announcement sounded like to me.