I like this: it makes the class much more viable than before IMO. A couple of things that come to mind:

Bonus Feats: I feel like spellsword levels should stack with fighter levels for feat purposes.

Channel Spell: How does channel spell work with more than one attack in a round? It seems intuitive that only the first attack carries the spell effect, but the description leaves it a bit ambiguous.

How does channel spell work with spells with long casting times? Move action is fine for spells that normally take standard actions, but it also allows for a way to get off a quick break enchantment or Symbol of X. I wouldn't say broken, but it is a really nice cheap-and-dirty quicken spell in some cases.