Personally I would definitely wish to see the Enclave making their comeback after being defeated by the Brotherhood of Steel in the Capital Wasteland. Like the Galactic Empire from Star Wars, the remnants that managed to escape the devastation on the Air Base hid underground for decades only to return in full force in whichever region Bethesda decide to set their new game in.
Just imagine:
- Powerful fleet of airships, we mustn't forget that the Prydwen was constructed using materials found at Adams Air Force Base
- Vertibirds, this definitely would be in the Enclave's arsenal of transport and weapons of mass destruction
Only to find that the NCR is standing in their way after expanding their territory from New Vegas at their attempt to re-create, redefine America itself.
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I seem to have lost a Penny.