Upgrades, or the lack thereof, are to my mind, the biggest negative of BAEC. Flying with LATAM I'd get them all the time: status plus early check in always got me to the top of the list. But the business model is as it is.
I did see one LHRMEX not so long ago. A group of two women and a girl in the exit row just behind the door in WT were invited to elect one of their number for upgrade, presumably to WT+. I was slightly miffed they chose from a seat with so much legroom, but maybe they had paid the extra for that seat in advance?