Spells are in no way a "feel" thing that is optional. Either D&D has them or it isn't D&D. That's quite an edict, you say? Yes. Yes it is. Every influence of D&D - the works of Howard, Moorcock, Leiber, Tolkien, Smith, Norton, Dunsany, Farmer, Fox, VANCE, Merritt, Zelazny and on and on - has people casting spells. No, not exactly like how magic in D&D works (well, with one notable exception) but it's there.
That's not an option, that's not a maybe so it feels like D&D to me.
If legend is to be believed the very first root of DUNGEONS & DRAGONS came during a game of CHAINMAIL when Romans were fighting Britons and the player controlling the Britons declared that his Druid was going to call lightning. It's been there from the get-go. Before alignment, before magic-items, before anything else, there was spellcasting.
And it isn't just a feel thing, either. It's a mechanical thing. Remove spellcasting (and remember - spellcasting is removed, no back-dooring it with feats and powers and saying "aha! I removed spellcasting and my game is FINE Delver is WRONG QED!"), and whole parts of the game start to break down. No spellcasting? No magic items including no potions. No healing spells. Whole classes are gone. Whole types of monsters are gone. Whole campaign worlds are gone (PLANESCAPE? DARK SUN? SPELLJAMMER? RAVENLOFT? gone).
I love alignment and I'd drop it before I'd ever even remotely consider dropping spells/spellcasting. It's just...not an option. Drop those and you might as well be playing BOOT HILL with swords.