I think MCT should be reduced a bit, particularly domestic to international, I rarely have problems with connections of around 1 hour, though the current issues with ground handling aren't great, hopefully temporary.

But one very clear reason for allowing shorter connections is simply competition with other airlines. So if you are doing something like JFK to GVA with a 90 minute connection, then potential customers and website listings tend to rate that higher than a connection in CDG or AMS which is longer, and BA's shorthaul timetable is to some degree linked to the banks of inbound services to LHR. It's also a factor when looking at direct versus connecting services, so a customer may have a direct service open to them with another airline, but if they elect to go BA, with perhaps a 90 minute longer flight but saving £200, then many people would choose that.