The decision between the 2 really is a no-brainer, before you even start to examine the potential logistic benefits from basing 15 miles away from the USAFE F-35 wing.
And when did the DoD make any announcement regarding deploying the F-35 to the UK?
With F-35 total numbers expected to dwindle; the pressure to reduce the number of total F-35 bases (from the 40s down to the 30s); and the US focus switching to China and the Pacific, I doubt the present F-15 wing will be replaced for many years - and is more likely not to be replaced when it is retired.