Lee Pace has been killing it the entire series with his portrayals of the different versions of Day, You could credibly argue that Pace and the actress playing Demerzel are single handedly carrying the whole thing. Wife and I watched the first couple episodes of S3 and our reaction was pretty much "Where has this level of story been the last two seasons?". But then we realized that its because space magician strong woman of color character was largely absent and several aspects of the third season are running closer to the source material. Yeah Empire is fabricated for the show, but the core aspects of the Mule and the third crisis stuff is all there, at least in the first couple episodes we have seen. The biggest issue this show has are the two charisma vacuum magicians it spent so much time on and that Empire (especially Pace) is the most entertaining part of the show.
Mule is going to be an issue, because in the books his motivations beyond one note anarchist bad guy were never really explained (by design), but if they make some shit up to fill in that gap its never going to be able to meet fan expectations. For now, the guy playing the Mule is killing it at least. I can see ways this ends up awesome, but I can also see some typical pitfalls they end up having with the story. For better or worse, this season is the best so far and Apple TV has been on a hot streak lately. I remain cautiously optimistic.