I guess the plus side of this is more connections US(DTW/MSP)-LHR-CDG/MXP/AMS-EU will be possible using award tickets... that was not feasable before since just about all of the SkyTeam flights to European destinations from London were from LHR.
Bad part is LHR means more delays and it is also a madhouse compared to the idyllic LGW.... not to mention connecting in the UK incurs some additional taxes!