Tbh I'm fine with Paladins' Smite in BG3 being "as a free action, spend the appropriate spell slot to add damage to your next weapon attack. If you miss your attack, the slot is refunded." The only thing you lose is the ability to crit-fish smites, which I dislike as it feels too gamey. What, on the exact instant of the blow, your paladin knows that calling upon their god's power will do crit-amount of damage, and then still has time to call upon that power!? I much prefer the idea of "on the swing toward the enemy, they gather power and make the sword smiting."
However, Larian might implement Smite as a dedicated hotbar icon, which would be much worse. You wouldn't be able to combine Smite with any other applicable attack type.
But yeah, for many other reactions/instant actions (Bard cutting words, Wizard shield or counterspell, anyone's opportunity attacks) it's not great...
Yeah I couldn't give a shit about crit fishing, it's extremely gamey.
I hope whatever workaround they plan for Smite means that it won't be automatically blown on your next attack. It's one thing to not have any control over your reactions, it's another thing to be losing resources because of it.
Nothing worse than losing a spell slot/smite cast on an enemy that was already low HP to begin with. Or worse, on an involuntary opportunity attack against said low HP enemy, because we all know how sadistic Larian AI is.