Perhaps you should start thinking outside the box and not apply unnecessary rules to a small NHT airport with no heavy / super heavy aircraft and only 11% of the LHR atms?
Well I'll leave it to our ATC experts to judge what rules are necessary and which unnecessary.
And my reference to joining points was in relation to Heathrow, as was yours re curved approaches:
And let's not forget the curved arrivals and departures already in operation at LHR