MAD would make sense for connetions but that is rather well handled already with BA out of LHR. Getting to another population center, more central EU, would make sense as a second flight option. QF used to operate a FRA flight which seems to make more sense even without a connection partner unless they can/do sell seats with LH or other airlines from there. One of the big advantages to the nonstop from birth is avoiding connections for tourists but mainly for business travelers.