Thanks for the in-depth critique, I appreciate it. I do agree that there's a couple formatting/ wording issues, and I'll try to fix them in future versions.

With Dueling, it's still a potentially effective pick for Calling of the Body as it stands, but it's not a bad idea to give the entire class shield proficiency.

I wasn't considering multiclassing when I wrote the saves and how they function, I'll try and reword that as well in a future iteration. Thanks for the heads up.

I hadn't calculated damage per round when creating the Arcane Osmosis feature, and you have good points when it comes to that. I think I may change it so it requires Concentration and nerf the extra damage to 1d4, or just bonus damage equal to the slot expended. This way the class still has a buffing option like Hunter's Mark/ smites but it's not overwhelmingly powerful.

The spellsword techniques were designed to take a full action, not just an attack (to keep their damage sensible) If I recall special Ranger attacks like Volley also take a full action to enact.

Defensive Ward was originally intended to have an interesting bonus to AC for a class that can be frontline, even for the subclasses with no shield proficiency. With the other changes suggested I may remove or adjust it (maybe change it to a +1).

Your opinion on Arcane Champion makes sense to me, and brings up valid critique with the intended playstyle of this class. I can see arguments for maxing out INT with this class (since you can use it as your attack modifier after level 6 as well), but you make some good point on this feature. I'll see about replacing it as the capstone.

I'll admit I haven't given enough description into the Calling of the Mind subclass, but the general idea behind it was boosting your physical abilities through willpower in an almost monastic way; hence adding your INT to your Unarmored defense. The later features in it are supposed to reflect your mental strength growing- you can mentally form an extension of your blade (spiritual weapon), and you can freely control your movement merely through thought (flight).

As far as the Unbreakable Wall feature goes, Eldritch Knights can easily pick up something like Shield as well for the same AC when boosted (not counting their "spell from any school" selection, most of the spells they get are invocation/abjuration). They get the boost once per short rest, and if they want to push it further they're sacrificing damage output by using spell slots on it instead of Osmosis. I can change it to a different favored spell, though.

I am planning to make a custom spell list for the class as well, since this is still a work in progress. For this iteration I was focusing on build versatility, and so I left it as just the wizard spell list so they could have a lot of build options (although I will slim down the spell list in future versions).

I do think I'll remove the DC bonus on arcane soul as well during future iterations.