I cannot see there being a great deal of pressure for BA to increase super junior command pay. As far as they are concerned, you join BA as an FO and serve your time as an FO until you gain the seniority for a short haul command perhaps seven or eight years later, by which time your command pay would be more competitive. If a new pilot is lucky enough to join at a time when command seniority is unusually low, they will see it as that new pilot being in the right place at the right time, and so obtaining a super junior command with its associated payrise. There possibly is some pressure to increase junior FO pay, which may then increase the low end command salary as FO pay is currently 75% of command pay across all paypoints.
More likely, if it is ever determined that there is a problem with recruitment numbers or junior pilot retention, then I would predict some kind of bonus payment after x years within the company, rather than a skewing of the salary scale.
This period of super junior short haul commands is almost certainly a blip. We had a recruitment ban for many years, and then suddenly we are in a period of rapid recruitment and postings and promotions movement. As that stabilises, short haul command seniorities will rise again.