My GM has come to the conclusion that the following feats are insufficient.
Arcane Armor Training
Arcane Armor Mastery
Arcane Strike
His fix is to remove the Swift Action requirement on all three.
For the two Arcane Armor feats, his other suggestion is to make AAT a -15% to Arcane Casting Failure, and to make AAM a -30% to Arcane Casting Failure, rather than the current -10% and -20%. Any non-multi-classed arcane caster is going to be spending 4 feats to get the use of AAM (two for the armor proficiency, two for the feats). If they choose to use a shield with that, it's a 5 feat tax for the ability to cast in a breastplate and use a Mithril large shield.
For Arcane Strike, his comparison is this: It's like Power Attack, but it doesn't reduce your to-hits in return for doing half the damage (or 1/3 for a two handed weapon.) and making it magic for things that are only hurt by magic. I think that the fact that it stacks with PA is enough of a bonus...but it does become kind of moot once you've got actual magic weapons to work with, since it doesn't seem to stack with the damage bonus for a magic weapon.
Then your GM should make whatever changes he sees fit. Or make new feats.
Like:
Armored Mage [general]
prerequisites: Ability to cast 1st level arcane spells, Armor Training 1, Proficiency with light armor.
benefit: You may ignore the spell failure of any light armor you wear.