As of now, it's just basic commands. I have a group called "Outside" so I give exactly your example... "Alexa, turn on the outside lights."
Basic, but it works. You can put any lights in to any group you want, and each light can exist in more than one group. I've got groups for individual rooms, groups of lights in individual rooms, and groups for multiple lights in multiple rooms ("upstairs", "downstairs", "main floor"). This is independent from the groups in the Wink app. It's both good and bad.
Not that I'm an expert, but what I've read suggests the Echo platform is designed in such a way that new capabilities can be added by developers. For example, Nest could develop interaction that would allow you to give commands to set temp, home/away state, cool/heat, etc. GE/Wink could, if they devote developer resources, add such capabilities I'm guessing. I suppose we'll see.