Depending on who you speak to, lipsticks can either be simple to formulate or very complicated. In my opinion they are a little of both. Simple because it is one phase made up of waxes oils and colors with some fragrance and preservatives thrown in. Complicated because there are so many things to track with such a simple formula - sweating, melting, stick hardness & shine, feathering, wear time, good mold release, flaming, etc., some of these can be very difficult to trouble shoot. Some attributes that a consumer would look for in a formula would be an easy to apply luxurious application with even color lay down and nice shine, an elegant creamy long wearing product which is non-transferring and non-staining and in a wide range of colors. This describes the ideal product that is also cost effective and readily available at any cosmetic counter.
From a formulation standpoint, that ideal lipstick is made up of waxes and oils that are all compatible with one another. The predominant oil is usually food grade castor oil which is a very good solvent for pigment wetting and grinding as well as solubilizer for waxes and other ingredients in the formula.