Enough has been said about Theurgy already. Not much more to add there.
For the War Mage, I think it is a good start but perhaps needs a bit more tightening of the concept, right now it seems a bit all over. In my mind what should make a "War Mage" different from either an EK, Evocation Wizard or Adjuration Wizard should be a distinct focus on mass combat, specifically spells that do area damage and protecting multiple targets at the same time. Stay at the back of the unit and cast out AoE damage, protection spells, and physical enhancement spells (like blur, haste, enlarge, etc.). While the EK, Evoker, Adjurer, or Bladesinger would be more focused on buffing themselves and single combat.
I would think that it should be 50% enhancements to damage spells and 50% enhancement to abjuration / combat buffing spells. The mix is a bit more weighted to the abjuration than I would like.
With that in mind....
Arcane Deflection A big help with Concentration checks which would fit into the concept of buffing you party, so not bad.
Tactical Wit Just not sure if this is needed. Not really a bad ability. I'd rather see some limited change to how magic works for battlefield situations, like being able to cast self only buffs onto others, but not sure if that would be too powerful at this level.
Power Surge This really does fit the description in my mind. No complaints here.
Durable Magic Nice ability but I wish it did something more to protect those in your unit rather than yourself. Also this the 2nd (possibly 3rd) ability that is about protecting yourself vs. only one so far that enhances AoE damage.
Deflecting Shroud Aside from the fact that this is another protective type ability, the Wizard just shouldn't be in the situation where a lot of attacks are coming in. Misty step, dimension door, etc. all keep the Wizard out of this situation. This would be nice against a horde of goblin, for example, but at 14th level that shouldn't be your concern. Anything with comparable CR would just laugh off the 7+ damage. This seems to be just too little too late.