I do aprove the idea of having transparent hud and having your health bar different color (and being over everyone's else).
I do not aprove the idea of having a switching minimap or different ping colors, I do not think this is very useful.
However, I would add something aside the allies face (top left) to tell us when their ult is ready. You can know that by bringing up the scoreboard, but knowing that your shen's, ww's, karthus' or amumu's ult is up could make a serious difference in teamfights. Something such as making their faces green when their ult is up and red when its not, standard colors when unavalaible (not leveled yet, or inexistant such as karma's one or udyr's one) and gray when the person is dead.
This is an example, thought anoter idea could be better then mine. Just knowing that the ult is up or not would be a nice add'on in my opinion.