Come on now - repeating with the opposite system's version is close to a repeat, considering now all x360 GWG's work on X1. It's basically a loophole.
Close but not really. You can still grab the XB1 or 360 version if you've got the other. Is it a bit cheap? yea (though I don't mind it), but it's hardly a repeat. They're different platforms with different userbases, hypothetically why should someone who only has an xbox 360 never get say, dark souls 2, just because they gave away dark souls 2 on XB1 at some point?
If you're talking about strictly BC games that work on XB1 aswell, none of the 360 GWG's that work on XB1 has been repeated either. The only 360 game that's been GWG since November that also has a remastered edition is SR4, and the XB1 version hasn't been free yet.
Either way that's a completely different situation from repeating the same game, for the same platform twice, which they haven't done and I seriously doubt they're gonna start it in June, the same month where E3 takes place and is typically one of the biggest months in the gaming industry.