Thank you for the comment.
I want there to be some conscious choice between which knowledge skills to increase. To be honest, adding all skills to the Scholar's class skill list pointless, because of Theory and Practice and Use What You Know. In the end, they're effectively proficient with all practical skills they care about, whether or not they spend points on them.
4 + Int is deceptively low. Remember that all of their abilities are Int based, so that's equivalent to 6 + Int for other classes, and in later levels they'll be getting more than rogues.
The Scholar's spell list includes all Sorc/Wiz spells of 0th to 6th level, and they can prepare any spells from this list, like a cleric. They don't really have a spell list. Their vast knowledge of spells comes from, well, their vast knowledge. Unfortunately, they're still mortal, and so can't really both know everything and do everything. I'm really not sure if the current situation is balanced or not, to be honest.If he is a scholar, why doesn't he get 9th level spells? The reason spellcasters are op is because of the variety of spells they can cast. If you have a spell list, you can make it reasonable.
giving a d4 Hit die to any classs that doesn't get 9th level spells is just cruel.
Also, some of the Master Lectures are really, really potent. They don't have any of the unrestricted, game-breaking power of 9th level spells, but they are still very powerful, and can't easily be replicated by any spell. One of them gives everyone in the party Evasion or Mettle for 24 hours.