Do the size categories of available creatures change for a small or large druid who is using wildshape? For example, it states that a Level 5 Druid can take the form of a Small or Medium creature. If he is a Halfling, should this instead by a Tiny or Small creature, as otherwise he can grow a size category, which a human druid cannot do until Level 8. This gets even more ridiculous with large or larger creature, such as Giants.