Autistic DM (he/him)
I think we've got the core theme down; it's a warrior that trained both body and mind to merge spell and blade. Eldritch Knights are Fighter that have practiced a bit of War Magic (abjuration and evocation), Bladesingers are Wizards that have a bit of Martial Training in order to be both a decent warrior and full wizard. A Stabnerd/Arcane Gish would be a warrior that looked at both of those traditions, said "nah, I can do better", and spent years of their lives honing their body and mind to be able to flawlessly merge spell and weapon.okay, do we have anything else to bulk up the concept beyond the purely mechanical and ideally theme subclasses around?
The subclass could be different traditions/styles of merging spell and blade. I say we take a note from the Bladesinger and Hexblade subclasses, and name some of the subclasses after previous editions' Arcane Gish classes. One can be called the Swordmage, and it would get teleporting abilities and extra prepared spell lists, another can be the Duskblade, and it would get buffs to Spell Striking, and another can be the Battlemage, which could be a 3/4ths caster with some Wizard abilities, like Arcane Recovery. I also think there should be a subclass that leans more into elemental damage types, so either an "Elementalist" or something like "Element Herald" for name would work, and another subclass for an "Antimage" or "Arcane/Eldritch Nullifier" subclass could also be cool. Something like a Death Knight from WoW could also work, getting spells that deal cold and necrotic damage and some necromancy spells.