I pretty much liked everything, except a few things:
I really didn't like that Bridget's second kidnapping happened without a fuss. I'd like to have seen something of a fight. It just felt so very unsatisfying.
We know Etherealists progressively grow more mad as they work with the powers. However, in the context of the book, the characters seem to remain at a static level of madness.
I somewhat feel this gives the Etherealists a bit too much power & wouldn't have minded that grand displays of power would be followed by either a temporary increase in madness, or some other drawback.
I mean, I don't see anything from stopping Lady Cavendish from pointing at every one of her enemies & getting people to claw their eyes out, just like Oprah handed out cars.
Gaunlet's overheat, but what stops an Ethrealist from just going overboard? We really were never shown.
Those are my two major issues. One I hope sees some self correction as the series goes on, the other is just a minor quibble.