I fly mainly in F (paid RTW and award). BA is still an ok airline for long haul flights. Others are better (mainly the Asian airlines and some European). others are worse (basically all the US airlines).
Since i am based in southern Germany i have choices.

And for the last 6 month i am avoiding BA and LHR whenever i can.

Some of the BA specific reasons are: the luggage thing - only 2 pieces 23 kg - Star airlines allow 3 pieces 32 kg each - and sometimes i have lots of luggage.
Then the small F seats (14 in the nose of a 747 vs. 10 (ANA, Thai) or 12 (CX, SQ) in the same space. NZ Business class also has only 14 seats in that area.

But the main reason is LHR. Alone the signs at security telling passengers of the consequences being not friendly to the staff at the security checkpoints makes me aggressive. I still believe i am the customer and want to be treated like one.
LHR compared to the other big airports in Europe is likely the most desorganized airport with the longest lines. And most other airports treat premium passengers far better.

So i have taken my business elsewhere. Even was using AA (yuck) - connecting thru FRA to avoid LHR.