my thoughts are that subway is still experiencing an identity crisis on which market they fit into.
a few years ago, they nab jarid and promote a healthy, low fat meal.
next, to counter taco bell's ever rotating menu, they offer up quesadillas.
then, they delve into the pizza market (evidently to counter the whole jet's, little ceasar's, pizza hut 3-way battle here in the states).
this is followed by a [short lived] return to the healthy kick again and offer up salads.
which is then bumped to promote some big and meaty and cheesy subs in conjunction with a promotion with nascar.