MOP - the only important question is one about birth outcome? And women's experience, perception, satisfaction and long-term memories of the whole thing don't matter? You can't mean that.
'better' outcomes, you say....a good example of the perils of language, and the way they can trip us up! 'Better' outcomes are not solely 'birth without intervention'.
A 'better' outcome for a woman with high blood pressure and (say) a breech presentation of a 5 kg baby might well be an elective caesarean, prepared for and supported etc etc - she'll go down on the stats as a section, which in public health terms is something we should be trying to reduce, but as an individual she might feel confident, joyous, relieved, supported and all the rest of it.
So putting all 'NCT births' through a statistical mincer and seeing how many are normal is not very helpful.
The words 'normal birth' form a technical term, not a judgment of worthiness. It's ufortunate that in English the opposite 'abnormal' happens to have negative connotations...not sure what the answer is to this one
Attention paid to vaginal/unmedicated/supported/confident birth is part of dealing with tearing...surely? 'God awful tearing' can be (not always) a risk with unsupported, poor perinatal care...and NCT is campaigning for better staffing, more midwives, continuity of care in labour and all the other stuff we know, from research, enables women to have a better experience...not necessarily always a birth without intervention, but a birth where the interventions are understood and safe and which make the experience more, not less, satifactory, whatever she feels has had to be 'done'.