The issue for the UK is that we've got a lot of those kind of disproportionate impact things. Occupational ones like taxi drivers etc. Social ones like multigenerational living. We know enough to see it, but not enough to see if it really does more to bring down the death/hospitalisation toll than the current age/medical risk ones.
Once we get to the under 50s, I suspect there will be more arguments. Personally I think we're likely to see some postcode targeted scheduling, but I don't know about what else they'll do. The good thing about the current UK system is that it "sounds fair" and it's relatively straightforward to administer.
Anything new would throw up new anomalies - yes, mum and dad are covered, but what about 45 year old granny who picks them up from school etc etc. If everyone's a priority, no one is - let's hope the vaccines keep working and the suppliers keep delivering (in steadily increasing quantity)