Ground is considered life because it is a form of earth, the ground you seem to be refering to, is rock which is also another form of earth. They dont need a another defence school, ice already has that spot. Water is already a part of storm and ice so there is no need to give water its own school.
by the way,all of your suggestions seem to be straight from the elements of pokemon
these are different things with different versions of what they consider "the elements".
i think that we should have the element of spirit. i know a lot of people would think spirit is not an element. but its THE most energized thing out there so therefore i think its an element spirit can be with storm because they both are strong and have to do with energy
Balance is not order, but rather just all parts equally. Fire includes lava. Life includes ground and plants and animals. Humans are animals. Storm has wind, electricity (lightning), and water. Ice also has water. Death and Life would be spirit. Myth I think was added mainly to have a class that mainly summons. If you paid attention you'd see that chaos is death, and order is life. Balance is there for those who don't want to have to worry about resistances, but it doesn't have bonuses. It's definitely a school you'd want to have a second one with.