New skin is perfect. I have nothing against it. But please, keep Monaco and Monobook. Users should be able to choose what skin they want to use on Wikia. Look at Wikipedia - there are many good skins, and none of administrators want to remove them.
Updating two skins at same time is hard? Just don't update older skins. Or update them with only supported updates.
Keep old skins, or remove Skin tab in Preferences, because there is no point of it with only 1 skin.