While by no means perfect, this wrapped up most of the plot lines I care about. The "spoiler" at the end honestly sounds like the beginning of a thread that would take more than a single book to explore so I'm doubtful that a fourth book would really be the end of the series. Not that I'd be against another trilogy but it would have to have a very different feel to the series if it was centered around the same characters given their wildly different dispositions between the beginning of the series and where they end up at the finale of Tyrant.