My hostas came in very skimpy this year. Usually they are full and lush, some with lavender flowers and some with white scented blooms. They are very old. This past Oct NH had a freeze. Will they bounce back next year?
Certainly the weather and environmental conditions can effect the growth of your plants.
There are a few disease or issue with Hosta.
Your plants also may need to be divided if they are older.
Here are some links for you.