Sometimes EP Kaolin is the best suspender in a glaze, sometimes it isn't. These are the same 85% fritted glaze. A (left) employs 15% Old Hickory #5 ball clay to suspend it, B (right) has 15% EPK. B settles quickly, demands low water content or it runs like water, it goes on very thick even if dipped quickly, it dries instantly and creates uneven thicknesses. By contrast, A goes on like silk, doesn't settle, dries evenly in about 10 seconds. What a difference! All simply because of using a different clay to suspend it.
In ceramics, glazes are suspensions. They consist of water and undissolved powders kept in suspension by clay particles. You have much more control over the properties than you might think.
Many ceramic glaze benefits and issues are closely related to the thickness with which the glaze is applied. Many glazes are very sensitive to thickness, so control is needed.