On the topic of misses not making sense when they deal damage:
It's because of crap rules like Reaper and martial dailies and whatnot that I didn't play 4e.
As for fireball, it doesn't do damage on a miss. You get a save for rolling in a ball, diving behind furniture, etc. You're still in the middle of a fireball.
That's a nonsensical distinction. What do you think a "miss" on a melee attack represents? Unless you rolled a 1, you missed because you
didn't beat the AC. In other words, the attacked creature likely deflected the blow with his shield, his armor, or his naturally thick skin. Or maybe he even dodged. Regardless, these are the type of events I don't expect a creature to be able to sustain indefinitely. Even dodging is strenuous; and likely not a little bit either.
If there's something that's unrealistically abstracted, it's omitting damage on a "miss" - it's pretty jarring to assume a creature can take a pounding with impunity, even if he's got solid armor. Particularly a Kobold. It's all fine that his skin is a little scaly and perhaps he parried, but it's still a
small, fragile Kobold - a massive strike is still going to hurt him, and if the attacker is sufficiently strong, hurt him enough to take him out of the battle.
Frankly, the argument for half damage on a miss for a fireball is
weaker, not stronger. If the fireball is an almost instantaneous explosion, then if you've covered yourself up well, your cloak might get charred, but you should hardly even be warmed. Incidentally, that interpretation jives better with the fact that fireballs do not
necessarily incinerate the environment - the temperate is high, but the heat energy not necessarily present in enough quantity to cause significant heating. Enough to burn skin, perhaps seriously, but well shy of the hundreds of degrees necessary to cause fire.
There's lots of nonsense in 4e which I hope 5e avoids, but this just isn't it. Sure, it's a simplification of reality (which is necessary), but it's not a rule purely for the game's sake - it makes sense in-world.