Hmmm, I've never seen a pack of them that didn't seem hard. Every single pack on the shelves at Whole Foods here are fairly hard. They always seem within the expiration date.
Marshmallows never seemed vanilla-flavoured to me. Just..... sweet. The Dandies I had were very strongly vanilla flavoured.
I think I ate two or three of them and ended up throwing away the rest of the pack. That was an expensive disappointment! I have seen Sweet & Sara's recently, but they look so sticky. I haven't tried them.