I don't know what it is but I find that I always end up with an overload of blue and green glaze shades! Maybe it's because I wear a lot of blue (and variations of blue) myself? Despite all my blues and greens I've had a hard time getting a good result in cobalt- part of the reason is that I have a very heavy hand with glaze and I put it on too thick. Finally though I think I've mastered this glaze and I'm actually getting consistent results.
So my big question is...what colors do you want to see that I don't have right now? I know there are entire color families that I ignore completely (yellow comes to mind- a color I never wear!) but the dilemma is whether or not anyone actually is looking for those shades. I'd love feedback on what you'd like to see!