Ok, going over it again I think we've nailed down a lot of the class. Just a few sticking points. This is where I think we'll veer off and have to slightly different final versions.
on SwordMage Warding...
You can project a magical ward around yourself, affording you some extra protection against enemy attacks. You gain a +1 bonus to AC while conscious and wielding a martial weapon. This bonus increases to +2 if you are wielding the weapon in one hand and the other hand is free.
I understand that you feel on some level that this is an archtypical feature of the class, and its one thing we have to disagree on. I really don't see it as anything special at all when compared to Fighting Styles.
* I'd simply rename it Warding Defense and put it under Fighting Styles as is, while removing the normal Defense option.
* I personally can't see where this as a class feature is better or more "magically evocative" than Aegis, which is what I'd use as the level feature here. It gives customization of the type of swordmage to play (offense, defense, control).
* I also still don't understand why a class feature you feel is Central to the class - discriminates against users of 2-handed weapons.
* Even raising the bonuses to +2/+3, with the restrictions listed, this just isnt a good enough class feature.
Honestly, I think this will push me to doing my "minor variant" version, starting with this change, then adding Aegis in as the class feature for my version.
FIGHTING STYLE
Eldtrich Warding
Starting at 1st level, using your magic combined with the magic of your Weapon Bond feature, you can project a magical ward around yourself. At all times you gain a +1 bonus to AC while conscious. If you are wielding your bonded weapon, this bonus increases to +2.
NOTE: This would replace the standard Fighter's Defense fighting style option.
However, if you are heart set on SWORDMAGE WARDING as a 1st level iconic feature, it needs work. So lets see...
Eldritch Warding
Starting at 1st level, as a reaction to being attacked, you can activate a magical ward of defense on yourself. This force ward lasts until you lose Concentration or 10 minutes whichever comes first, till you dismiss it as part of any other Action, or you fall unconscious. This ward grants you a magical bonus to AC equal to your Proficiency bonus.
Additionally, when you take the Dodge action on subsequent turns, you can make a melee weapon attack as a bonus action.
Once you use this feature, you can't use it again until you complete a short or long rest.
* It now acts like a concentration spell, not a fighting style.
* It scales with level, making it more iconic and useful.
* Give a slight edge when using Dodge. Cant get more "defendery" than that.
* Limited by 1/encounter (short rest).