Apple limits settings (and rightly so), but the iOS auto correct really needs some settings. Namely – the option to turn it off would be nice. It seems to be the most painful feature for most iOS users I know.
In my usage – a bad auto correct is far more common than a correct one.
If thy really dot want settings the default behavior should be opt-in to correct – and red underline on mis-spelled words. This would change the ios role from “know-it-all” to “helpful”