But [MENTION=6785438]Warmaster Horus[/MENTION], they aren't "vague" or "seem to support a bonus to a damage roll." It states it flat out.
"...you can add your Intelligence modifier to the damage roll of any wizard evocation spell you cast."
It doesn't "seem" it says, it says. You add it to the damage. Not "per target", not "per dart". To the damage of the spell. 3 x d4+1, then +Mod. That's what it says. It's not "opinion" or "interpretation"...it's basic reading comprehension. .
Does +30 to a Burning Hands spell make sense to you? A Fireball could do +40 or more. Does that make sense? It's a 10th level ability, yes. But does it make sense that your Int. mod. should be exponentially more powerful against a group than an individual? Your Int. mod. is the same no matter how many people you're fighting.
Again, if you want to take "the Word of Mearls" as law/"official", that's up to an individual table...and fine/no skin off my back if you do. But the only "RAI" that is portraying is the AI in Mearls' own game...and I will continue to believe [until proven otherwise] that it was a simple mistake/not thinking it through to say "per target", since it doesn't make sense for that to happen.
This trend of being able to [purposely] shade "misunderstanding/lack of clarity" where there isn't any is something of a hot topic/button pusher for me. I'm not trying to "one true way" it or tell anyone they're playing "wrong" or whatever. Play how you want. Just recognize it for what it is instead of feigning "Oh. I don't know/not sure what this means..." when there's nothing to question. Granted, there are vague or unclear rules in 5e. That's a given. It's bpractically part of D&D's DNA at this point. But this? This is not one of them.