Does anyone really think it would be supportable to include interviews as part of the process?
One benefit of VR / NVR tests is that they have definable right / wrong answers.
Almost anything else needs qualitative analysis and is open to subjective judgement. Especially an interview. I suppose an interview oculd be recorded and then analysed fro number of similies and metaphores used, number of times an opinion is backed up by evidence, timing the pauses and lengths of hesitations...
They work fine for private schools and scholarships, presumably, because those schools are not by definition equal opps. They are looking for 'the right fit' - something which may be much more discernible in an interview. State funded schools must do all they can to assess on cognitive ability alone.
Can you imagine the appeals process? Suspicion of every kind of ism, discrimination against children who have EAL, not to mention an enormous disadvantage for children who have not had access to dinner part conversations and are not used to expounding their opinions to adults. The results would differ wildly depending on the skill, approach and personality of the interviewer, what sort of person a child finds easiest to talk to etc etc. Too many variables.
It just isn't workable, and is disallowed in the admissions process for a v good reason, IMO.