In a way BA already has dynamic pricing, not in the same way as some other airlines but by varying the substantial redemption fees. Carrier surcharge they call it and while levied on both redemption and revenue fares this is offset for revenue bookings by lower base fares. Now accruing Avios with other airlines it’s clear that redeeming for BA operated flights is more expensive than on other airlines due to these fees. These surcharges are also tailored based on originating markets as you can see by checking a First redemption from the USA where fees and taxes easily amount to far north of $1,000 per passenger on top of the Avios required.