Otterscrubber said:
IMC we decided that yes you can turn into an advanced creature with Wildshape, Polymorph or Shapechange since we could not find anything in the rules to say that it was not an option. Some posts in this thread seem to think that you are limited to only the standard HD listed in the MM, if you can tell me where this is printed I would appreciate it.
The trail you must follow to get to this ruling is rather roundabout, but still clear. Here goes:
The Wildshape class ability functions as the spell Polymorph, with some exceptions that are not relevant to this question.
The Polymorph spell functions as the spell Alter Self, with some exceptions that are not relevant to this question.
Alter Self states: "You can freely designate the new form’s minor physical qualities (such as hair color, hair texture, and skin color) within the normal ranges for a creature of that kind. The new form’s significant physical qualities (such as height, weight, and gender) are also under your control, but
they must fall within the norms for the new form’s kind. You are effectively disguised as an
average member of the new form’s race." (Emphasis mine).
Finally, under the Improving Monsters section, it states "Each of the monster entries describes a typical creature of its kind."
And there you have it. You can only Wildshape into the typical animals and plants listed in the MM, not any advanced versions, versions with class levels, or versions with templates.