Most importantly, you have to meet your employer's optimization requirements. If you decide to do even better, it's important to use common sense. Those long straight lines that are not aligned lengthwise or crosswise will cause you a lot of problems in the game engine when the texture is scaled. When scaled, all the pixels around the edge will be blurred and you will see blackouts on the edges. So make them all quads and straighten them to a line. The loss in polygon count is negligible compared to the visual loss. But if you have reached the polygon limit, use the Reshape Islands operator. I showed how to do this in a previous post.