Wow, that summary is a pretty big disservice to Mass Effect. The story is so much more than that.
Like I said, it's comperable to starting Star Wars at episode 6 or picking up Watchmen at the 11th hour. Is it possible? Certainly. But you are doing yourself a major disservice and you are going to miss some things. Mass Effect is, ending shenanigans aside, a masterpiece that deserves to be experienced in it's entirety. The comics at the start may help that to a point, but it's not much better than just reading plot synopsis on Wikipedia. I wouldn't recommend it to anyone who hasn't experienced the first two for that reason.
I mean that depends on your definition of value, but I'd say almost certainly not. Mass Effect isn't exactly a rare game by anyone's definition, and WiiU is hardly a popular console. Adding to that, it's the worst version of the last game in the trilogy. It's available digitally pretty much everywhere, and even if the PSN and Xbox Live disable online for PS3/XB1 you still can pick it on *shudder* Origin.