Considering rumors/specs are already swirling on Shield 2, and with the recent price drops on Shield, I'll bet Shield 2 will be out by late 2014.
I had same concern, really wanted to wait for Shield 2 (as I've not been impressed with Shield specs), but I *really* wanted to be able to stream PC games (esp w/ Wolfenstein out now, and Watch Dogs out next week), so I went ahead and splurged on Shield 1. I've kept the box & packaging though, so if Shield 2 suddenly surprises us in the next 30 days, I can return to Amazon for refund. If past the 30 day marker, I can always sell the unit used in it's original packaging via Amazon.
Now I've just got to figure out what to do with my gen1 Vita. It was already languishing prior to Shield, and now that I can play PC games on a handheld, Vita seems completely redundant
(well, except for periods of time where I don't have net connectivity, but then I'd likely be reading/working or end up playing Candy Crush Saga, lol)