I don’t often check a bag when travelling on business, but for longer trips I have noticed an improvement recently when arriving at Heathrow, with bags often arriving as I get to the belt.
Outstations are a different matter. The T5 baggage system certainly segregates bags, so there’s no excuse for it.
For a long time, baggage handlers at Heathrow were notoriously Communist and would refuse to give F & J pax’ luggage priority. Something must have changed when they moved to T5.