Draw3Cards is a SE 1.0 site for MtG. I am not active there anymore, but I have asked a couple questions there that I believe would be beneficial to have asked here. Obviously, copying every non-duplicate question from there seems unethical so I only want to ask my questions here. Would this be acceptable?
As the owner of Draw3Cards, I can say that there's nothing in our TOS to stop you from doing that. I don't know about the ethics of Board Games or SE in general though - this could be considered rep farming.
Can I ask why you would want to do this? Were the questions not answered properly on D3C? Or are you just trying to "artificially boost" the content in Boardgames SE?
I won't complain, no matter how you do this.
One thing though - right now, the way I see it, Magic is the #1 game tag on Boardgames, way past any other tag. I and others strongly think that there is room for a dedicated Magic SE site. If you agree, I think a better move would be to support the proposal for a dedicated site, and perhaps wait until it opens and ask your questions there. I'm not sure if Boardgames is sustainable or not without the Magic content - but it is my opinion that Magic deserves a dedicated SE nonetheless, even if this means a substanial dilution of Boardgames SE.
The only issue I can think of is that it will set a precedent for that behavior. While you happen to be the person who asked those questions (or so you say1...), what's to prevent me or another user with nefarious rep-farming intent from going and asking every question that's been posted on Draw 3 Cards?
I couldn't actually find anything about Draw3Cards' Terms of Service - IANAL, but it might not actually be legal to duplicate that content here. In contrast, at the bottom of all SE pages there's the following blurb:
Given that it's entirely unrelated to Stack Exchange, if it does happen to be legal, the worst that can be said is that it'll hurt D3C in it's page ranking (in that the exact same content on D3C will be competing with SE).
: I actually know @OrigamiRobot in real life, he's the person who asked those questions on D3C.