One small positive note about summoning: Your 14 dice are resisted with 6 dice from the spirit (assuming you're not oversummoning). You are very, very likely to get at least a service or two. And you can freely resummon when needed - all it costs is some drain. Granted, that can hurt, if the spirit rolls well, but more dice on your end doesn't change that either. So, for summoning, 14 dice is plenty. Of course, more is better, as always, but diminishing returns hits early with summoning.
The only real disadvantage to a lower summoning pool is that when you bind spirits, you want to start with a decent pool of services (since you're unlikely to add a lot with the actual binding).
Heightened Concentration is in Shadow Spells, which is why Chummer might not have it (or why it's not available - perhaps you need to add that sourcebook?).
What do you mean with Corporate Shamans/Summoners? Only those who summon spirits? Hermetics are fine? Why? (You don't have to tell me, but you might have to tell your GM).
I also just noticed you don't have counterspelling. Counterspelling is anywhere from useless to utterly essential, depending on how many mages you face and how many other mages you have. But it's usually good. There's not much to take points from, though. Buying a few ranks from karma is a cheap way to get some minor additional personal magic defence, at least.
