So there is a clear case for removing landing clearances all together in some cases. i.e by default you are clear to land. (USA/France style)
Late landing clearance is often just to ensure rules are complied with. Clearly this requires extra concentration in a specific area for a period, for both controller and pilot. - effectively to tick a box.
ATC spend their efforts to ensure that aircraft will achieve the required runway separation so it should be there by the time you get to the runway.
ATC role (for the landing aircraft) would then be to monitor for things going wrong and the only instruction you would expect to hear would be a go around.
Although as humans we are not that good at monitoring, so would this reduce safety?
- we might still have to concentrate on the problem but not "having" to issue a landing clearance might mean we monitor less effectively.