The following is what Emina McLean had responded to me on an email exchange with her.
We do perhaps disagree that mispronunciation using extraneous phonemes is a/the major cause of instructional casualties and/or The Reading Wars. That's not to say that it doesn't play a role, but in the schools I work in the biggest issue impacting literacy development is that phonics is not taught in any systematic way i.e. students are not learning how speech maps to print in any structured or explicit way and they are not learning the different between speech sounds and alphabet letters. I agree that we should ensure accurate pronunciation, but we also need to get everything right that follows on from that, including ensuring that all schools are following a systematic phonics scope and sequence.