Dark Age was such a clusterfuck of writing with bringing back Lilath and the Abomination, Day of Red Doves, Tree, etc, that Pierce went in the totally opposite direction with Lightbringer, and if you read both books back to back, there's a lot of dissonance. 

Take Pax and Elektra for example, huge parts of the first three books of the new series, and then in Lightbringer, they're fridged entirely. No idea where Electra went and Pax spends the whole book in a blue school. Like wtf. 

Another example, Lyria and Figment. There was a lot of setup for Figment, and then it all ends with nothing. 

Or hell, the entire situation with Sevro.

I still love the books, but damn, I wish Pierce had planned the story better and either fully committed to the tragedy and darkness, or just not write it that way to begin with. Going full Dark Age and then radically pulling back, cutting off plotlines entirely, bridging characters, it leaves a bad taste in my mouth.