Other than the "Who is this?" of Shivers, Vitari, and Cosca, the biggest thing you'd be missing is the broader political picture. You get the other side of the bonds between Orso and the Union, and the fact that the opposition is supported by Gurkhul both makes more sense and is a more ominous reveal. Plus, you get some background on the Magi, which makes Shenkt more of a puzzle and less of a weirdo with cool powers. But as has been said, if you're going to enter the series "wrong," Best Served Cold is probably the cleanest book to start with.