To be clear, I'm not particularly advocating for making english a phonetic language. I'm just saying it being non-phonetic does cause issues (and makes it frustrating, but also shows a very interesting history).
Assuming we wanted to make English a phonetic language, then your question is kind of moot: phonetic means we need to pick the pronunciation rules for phonemes, which would make other ways to pronounce these phonemes incorrect. Some of currently-correct english would become incorrect english.
> For example, I would guess that 50% of English speakers are non-rhotic
Note that accent isn't really what people talk about when they complain about pronunciation. The problem is that there's no mapping from letters to phoneme in any english accent: laughter/slaughter, draught/draught, G(a)vin/D(a)vid...