Shape spells are hard to balance: you can't have too few or else each one provides too much utility, but too many and the value per spell decreases. Should a new mage take 4 different Shape spells, or just one fireball and hope it can make a hole in the wall?
Additionally, the choice of elements combined with a not-great GM section makes it hard to get consistent effects from the Shape spells. A Fireball has a predictable effect with minimal GM discretion. But materials? The same office building wall could be made out of wood, plastic, or stone depending on the GM. Which spell applies to a bullet proof window? Is asphalt a type of stone? Is the futuristic road even made out of asphalt anymore? All of this ambiguity makes for a poor player experience using Shape spells.
Lastly, the spells themselves are poorly defined: "[the material is] putty in your hands." Does Shape Stone make a pile of rock, or Michael Angelo's statue? The spell allows you to move 1 cubic meter per net hit, which is a huge amount of material. Forget making a hole in the wall, you can move the whole wall with just 2-3 net hits. How far can you move material? How fast? Can you trap an enemy in a stone coffin with Shape Stone? Because they are so open-ended, these spells are prime candidates for homebrew to nerf or adjust them as soon as players start to get creative.