>>What seems really odd about this [wOr\S] thing for "wash" to me, is that not only is a [r\] inserted, but also the vowel is altered. "wash" without the [r\] tends to be [wAS].<<
Mind you that non-cot-caught merged North American English dialects very often have some analogue of historical /O:/ in "wash", such being [Q] here. You should also remember that in many NAE dialects which are horse-hoarse or Marry-merry-marry merged, the resulting merged vowel is between [O] and [o] and [E] and [e] respectively. Consequently, having an [r\] inserted would very likely have resulted in the raising of the vowel in "wash" provided it occurred before the horse-hoarse merger.
>>Presumably the r-insertion happened before LOT-unrounding in your accent. Many Americans have their THOUGHT vowel in words that have /wQ/ in RP, like 'wash', 'water', 'Washington' etc. and these are the same kind of words that favour r-insertion. So even though you have a change from [A] to [Or\], etymologically it's the less drastic [Q] to [Or\] (or possibly [Q] to [O] to [Or\].<<
Remember that LOT-unrounding in very many North American English dialects did not occur after /w/, and instead merger with /O:/ rather than /A:/ occurred in such positions in many words, "wash" being one of them.
Also, I doubt that there is actually a change from [A] to [Or\] occurring here, and rather that the form with [Or\] is actually conserving rounding which has been lost in the form with [A].
Mind you that non-cot-caught merged North American English dialects very often have some analogue of historical /O:/ in "wash", such being [Q] here. You should also remember that in many NAE dialects which are horse-hoarse or Marry-merry-marry merged, the resulting merged vowel is between [O] and [o] and [E] and [e] respectively. Consequently, having an [r\] inserted would very likely have resulted in the raising of the vowel in "wash" provided it occurred before the horse-hoarse merger.
>>Presumably the r-insertion happened before LOT-unrounding in your accent. Many Americans have their THOUGHT vowel in words that have /wQ/ in RP, like 'wash', 'water', 'Washington' etc. and these are the same kind of words that favour r-insertion. So even though you have a change from [A] to [Or\], etymologically it's the less drastic [Q] to [Or\] (or possibly [Q] to [O] to [Or\].<<
Remember that LOT-unrounding in very many North American English dialects did not occur after /w/, and instead merger with /O:/ rather than /A:/ occurred in such positions in many words, "wash" being one of them.
Also, I doubt that there is actually a change from [A] to [Or\] occurring here, and rather that the form with [Or\] is actually conserving rounding which has been lost in the form with [A].