As a battlemage nut, I'm of the opinion that the swordmage could use a general redesign.
You've already raised the first part: the class is unnecessarily restricted in terms of weapons. Spear-mages would be a natural place to start for battlemages that focus more on casting, since you could easily draw on staff-mage traditions. There's also no reason that hammer or axe mages shouldn't exist.
The armor is another consideration; they wanted to have a forcefield replace the spell and most of the armor, but what they should have done was just go ahead and give the swordmage a +2 in cloth or leather armor and add on light shield proficiency, so that folks who wanted a swordmage who wielded two-handed weapons or a shield wouldn't be screwed over. If a swordmage wanted to spend a feat on heavy shield proficiency, then good for them, they've spend a feat to go from fighter AC to paladin AC.
Swordbond is freaking useless. They could have replaced it with Intelligent Blademaster and the property of Farbond Spellbade (treat a heavy/light blade as heavy thrown and have it automatically return to you at the end of your next turn) and had it work out.
Finally, the marks. Aegis of Shielding is fine, but Aegis of Assault should have been able to respond to an attack roll, not a hit, and Aegis of Shielding should have had that and speed penalty apply to the triggering target (like how Frigid Blade works).
I've had a few ideas for an Essentials Swordmage myself. It's still a defender, but it uses Defender Aura and a reskinned version of Feywild Guardian (that essentials fighter feature that uses plenty of teleportation). Intelligent Blademaster would automatically be included, and it would have the version of Swordmage Warding mentioned above. In addition, the class would have a Battlemage Style, where you get a benefit that fits with a certain style of sword magic, such as a style that focuses on slowing and binding the enemy, a style that focuses on illusions, a style that relies on endurance and arcane shields, and a mighty, brutal style that focuses on elemental attacks.
At-wills would still be standard actions, of course. Encounter powers, meanwhile, would be built like the Cavalier's Holy Strike, only you don't get one that you reuse, you get to choose from several of them as you level up, like regular Encounter powers. You could have one that dazed, one that pushed, one that immobilized, etc. Daily powers would be the ones where you get only one, but you have multiple uses of it per day, and the one you get would be chosen by which Battlemage Style you chose at level one.