Sirtis talks about that at Cons.Agreed, plus if you watch Troi's character over season 1 and most of season 2 her accent seems to change. Kinda weird.
Originally they asked her to do an accent to make her sound more "alien". She was told it was their(the writers) idea that all Betazoids sound that way............until Luwaxanna showed up and had no accent at all.
