Priest movement would still give priests a marked advantage over non-priests. I'm not sure, myself, if this is enough of an issue to prevent it from being allowed.
Would there be any *disadvantage* to being a P/T? A warrior switxhing to Trader incurs some serious disadvantages. If there are none for P/T, then will we see a rush of priests headed to Trader class? While that wouldn't necessarily hurt anything, it would turn the priest class into something not intended.