Hey,
I think Loremaster should be more expensive than that. I personally don't think it should be an upgrade, but if there is one, it should cost more than upgrading a wizard level. Not necessarily because it grants access to all spells, but because it guarantees that you always have the spells you'd want. I'd pay more than 35 points to always have throne of vine's and dwellers on my LVL4 life, for example.