Electricity wouldn't be as much of a problem nowadays with advancements in LED.
As for the set itself, the premise is brand new games, and better zones... So they may not even be Aztec, Medieval, etc. They could be four brand new concepts to make a 2017 onwards version of the show completely separate.
A one off special set in the 90's makes sense. A brand new revamped series, maybe not so much.
The main question isn't whether it'll be back on our screens because I think that one is pretty obvious now. What with new studios, paying for orchestrated themes etc. The main question is whether Merchant, Tennant or someone else will be hosting?
I thought Merchant did a VERY good job, and I also think Tennant would be received very well. It's whether someone else could surpass either of them... And now Richard isn't going to come back!