This.
I strongly believe the strength of D&D relies on resisting the temptation to make things generic.
Idiosyncraticities such as only the Rogue gets sneak damage while only the Ranger marks, only the Fighter gets Second Wind, etc is the cornerstone of making the game feel like D&D.
Sure they're all guys with a pointy stick, but that doesn't mean it's a good idea to let them fight the same.
I agree and would love to see this apply to separate spell lists for casters, but...