Of course the Biggest problem is that 97% of OneWorld European First Class flights all use LHR.

CX only have First to CDG and FRA
AA DFW-FRA all their other European flights are 2 Class 767
IB/AY and QF[Other Than LHR] are 2 Class with no First

Of the 3 New Members JL/MA/RG only JL into LHR will have First Class Suites, hopefully some JL European flights will eventually upgrade to Solo.

Meanwhile if you want to fly OneWorld First its very difficult to avoid LHR.