Between the standardized spell progression for non-Warlocks and that all spells function the same ... I think 5e already does have unified spellcasting mechanics. The differences between how Bards and Sorcerers know spells vs. Wizards and their spellbook, and Clerics and Druids having full access to their spell lists is not to me a meaningful enough distinction. And it's important enough to class identity to keep it.
Now, outside of the Core classes, should other classes have to hold to the same mechanics? No, I think Artificers are hamstrung by this system, as a Half-caster progression feels way too slow, but I don't think they should be Full-casters either. They probably need an Infusion casting system that is unique. Psionics, to me, has appeal because it isn't just spell slots by another name, so I think Psions shouldn't follow the standardized spell mechanics and just ignore components.
Now, outside of the Core classes, should other classes have to hold to the same mechanics? No, I think Artificers are hamstrung by this system, as a Half-caster progression feels way too slow, but I don't think they should be Full-casters either. They probably need an Infusion casting system that is unique. Psionics, to me, has appeal because it isn't just spell slots by another name, so I think Psions shouldn't follow the standardized spell mechanics and just ignore components.
