As you say, the wrong end of the stick
A WTR is as you say different but there is nothing that stops you from applying for a PR whilst on it with no need to wait for a certain time (I know this for certain because this is what we did). If you do apply and get granted in under 3 months you may get a Section 18A condition.
It should also be noted that at least one person on this forum waited the 2 years as implied with a WTR and then found it difficult to get their PR in the time left before the visa expired.
You are correct about a visitor from the UK gets automatically granted a 6 month visa which can be extended, but you can apply for a 9 month visitor visa if you prefer. So it hasn't changed, 'automatic' visa is still 6 months.
Ian