Ex-brit in Toronto.
Re: Multiple landing clearances.
In Canada it is a little different again to what was quoted above from the 7110.65. In the US example a landing clearance can be issued to an arriving aircraft when it is not number one to land and there is an intervening departure ahead also. In Canada multiple landing clearances are only issued with reference to arriving traffic. A landing clearance will not be issued with reference to a departure until the departure is rolling and the controller believes that it will be airborne before the arrival crosses the beginning of the runway. The responsibility for separation rests with the controller.
Extensive surveys have taken place logging thousands of movements to obtain accurate runway occupancy times (ROT). If a ROT for a runway is demonstrated to be 50 seconds or less the runway will be approved for 2.5 mile arrival spacing. It is permissible, however, that aircraft on visual approaches will be closer than that. On this side of the pond the onus for separation (and wake turbulence avoidance) on a visual approach is the pilot's unlike in the UK where the controller is still responsible.
This is why airports here can have very high arrival acceptance rates in good weather which fall when visuals are not possible and fall further when it goes less than 3SM and/or 1000'.
What is wrong with using years of experience and your skill to separate aircraft? You're either cleared to land or you're not. There is no confusion, unlike the UK's "land after", "after the landed, cleared to land", "land after the departing". How is a non-native crew supposed to make head or tail of the nuances between these and know what his responsibilities are? Have some of these now been removed from use? If so, why?
If you're a radar controller and you have two aircraft on converging headings and wish to climb one through the other, do you parallel them off to make sure they can never come close or do you use your experience and skill to decide whether the climb through can be completed in time? Is that not a form of anticipated separation?
I don't think its a case of better or worse, its just different. We all have different rules to work with, be it our ATC rules or noise abatement. I could clear an aircraft for take off every 30-40 seconds and move 100 departures an hour but that would take an ideal world, which we just don't live in. If things are done differently, its usually for a reason but the reason may not be apparent to the user so having the user saying ATC at ABC is way better than at XYZ is about as valid as us saying pilots at CBA are better than pilots at ZYX.