The abundant amount of characters with all too complex names with pronunciations will make your mind stutter while reading.
While many of these characters are one ofs, with no future mention, it makes it difficult to make a commitment of digestion of characters. The useless filler which could have been used to give better physical descriptions other than graceful, old, or slobbering fool would really help put a face to some of the aforementioned characters.
Another really big issue I had was imagining the monsters. Many of the mentioned monsters have little to no description, no sense of varying danger based on strength or ferocity, and scarce physical description.
I was constantly putting the book down to look at a wikipedia site to see what the monsters were or looked like.
Lastly, the combat scenes. Whirring with a pirouette does little for the imagination. The signs were also very dull. No sense of stamina, no knowledge of how they were cast or where they were learned.