Wow, the errata really nerfed that class feature. If you do as they suggest in terms of when to take the class, you get expanded spellbook at levels 5, 8, and 11, so that's a 3rd, a 4th, and a 6th level spell. Since these are all spells you could put in your spellbook by purchasing the appropriate scrolls, doing so would cost you (including the cost for scribing) 2662 gp 5 sp.
3 levels of class feature =/= 2662.5 gp.
What makes SO MUCH MORE SENSE to me is that the whole point of being a master specialist is that you are really good at the school of magic you do, to the point where you can essentially research wizard versions of spells in your schools as part of your normal level advancement (you could do this anyway, but it would take you time and money).
My DM will almost certainly agree with me, so I still have the question above.
<snip>all wizards would be able to cast all spells by adding them to their spell book, which can be done by varies means outside class features such as this one.
Or am i mistaken, and if so, why?
The reason this is not true (in my re-interpretation which ignores the errata) is that normally you can only add wizard spells to your spellbook. This class feature would be an exception to that (like you get from Wyrm Wizard or Recaster, but with the restriction that the spell be one from your chosen school) which added the spell to your class list.
It's not broken, or at least not more broken than any of the other ways there are to get non-wizard spells in your spellbook. Which of the spells in the above list is going to break a transmuter gish at 5th level? More than what he can do already?
