Thoughts on a Spellblade/Spellsword Champion; needs feedback and suggestions

Just had a thought on this while thinking of Celes Chere from Final Fantasy VI. Basically, the idea of this Champion would be a melee fighter who can build AD, but her basic attacks actually are purely magic instead of physical damage. It wouldn't be a case like Orianna's or Diana's passives, but more like what's making Runeglaive so broken right now, only it's on every attack. HOWEVER, there'd be a few downsides.

These are just brainstorming ideas right now, and I'm trying to pin down a good theme for this Champion, so suggestions on development are appreciated.

• Passive: Basic attacks deal magic damage instead of physical damage, but are only 90% effective (ala Kalista) and cannot critically strike. Crit chance bestows a different effect on this Champion.

• Q - Spellstrike: Your next basic attack deals bonus magic damage and raises a spell shield for 1.5 seconds, blocking the next incoming hostile spell.