And I disagree that cooldowns are more tactical. It's less. In 5e, the wizard has the choice to cast fireball twice in one encounter if the party feels they need it. Sure, the wizard can't cast it anymore until a long rest but the choice is there. And in a desperate situation, it may be deemed necessary. Cooldowns? Nope. Not an option.
And this example is just the fireball too. It gets more complex too: Do you use your 3rd level spelllslot for that counterspell? Or will you upcast a Sleep spell to put the big beastie to sleep? Maybe you will haste the fighter instead because the enemies are fire resistant?
With how 5e spells work, as well as spellslots and upcasting of spells for bigger effect, it becomes a LOT more tactical than cooldowns can ever be, really.
