My point is that what you are saying makes sense but in most cases it just doesn't happen because you are either in SwO or ShO, there are practically no cases you'll be swapping unless there is a tank swap mechanic which most PLDs would swap oaths in anyway.
Basically it doesn't change anything that PLDs already do and it won't until some other mechanic involving the oaths is introduced. PLD looking to do more damage as MT just tank in SwO anyway.