Should we let this topc keep going with discussing the posibilities of more Giga Coasters coming up? I'd say, look at China. The parks there have money, but they don't have a Hyper yet with the exact same marketing appeal (as is true for many US parks: If they get a Giga, their old Hypers become obsolete). And planning permission seems to be no problem.
Other than that, I think Heide is a possibility, and perhaps BGT (Hey, they've been rumoured to get a B&M Hyper for years, and if they can fit a Hyper in there, they probably can shoehorn in something bigger as well).
I'm not sure on Japan, seeing as the parks there seem to have quite some draw, but we rarely see big coasters going there. They have a few Hypers already, but I think the market isn't full there yet.