At first glance, I have no idea the power level your aiming for.. I like the class though, I just don't think many DM's would ever allow it. The closest thing I can think of to compare it too is the Duskblade.

Your class has weaker BAB, same amount of good saves, better HD, much higher AC, and a lot, lot better spell list.

I mean, the only thing the duskblade can even bring to the fight is a full BAB and the ability to wear armor. It's spell list is so bad, that the fact it gets 5th level spells when you don't, hardly matters.

The AC thing is also arguable.. A duskblade, with 16 Dex, can wear Breast Plate and use the best shield he can.. That gives him an AC of 20 of the top my head. Your sage, is gonna have a crazy Cha, since everything is tied to it. And likely a better Dex as well, but we will ignore that. So 16 Dex, let us say +2 Bracers and a Cha of 22, which is 25. However that's getting pretty high level to grab those class features, however getting a mid 20's Cha score isn't hard by any means. So the duskblade hits more often, with weaker spells. While you hit with better spells, get hit less, and survive more hits.

Last but not least, you can full channel 5 levels before the duskblade ever can.

In any case, my tone during this post isn't angry or even upset. I'm just trying to give you the best analysis I can, which I admit isn't very good. However that's what I have to say. Take it as you will.