No surprise.
I don't simply hate Suwon because of his position on the evil side, but his lack of perspective also shakes up a lot of uncertainty. This of course can end with a forgiving to each other, and a number of parties have put forward the demands of war.
I feel this arc is the most important arc and I want to see that flame grow from within. And seeing how Yona handled everything peacefully, the coup d'etat is expected not to be anti-climax.
I'm pretty sure this author loves Suwon with all its downfall and does not make him a fully evil, but a king who can fulfill the needs of his kingdom. Sigh ... imagine if in the end this childhood friendship game will take over?
I want to say that it's predictable but it's also not.