Bitcoin dominance did start to drop as the overall market was rising, but with the current bear market, it has only increased again. I think it will maintain it's position as a clear market leader for some time yet, but would like to see it dropping below 25%, that would be a sure sign of the market maturing. While one coin has such influence, it's difficult for even the best projects to break free from it's grasp. Hopefully over the next year it will make tentative progress towards that anyway.