The catch in blood magic (imho) are not the combat spells, but the summons and global spells. For Jotunheim, Illwinter is a must (cools down entire map), and ice devils and frost fiends can really help in the game, and are not all that hard to get. Get the SCQR (summoned creature quick reference)
http://ulm.illwinter.com/dom2/SCQRv0_5.pdf
And just look at the list of blood magic. Also note that everything in blood is cheaper than it looks because it's generally easier to get blood slaves than gems.