Ah, you are right, not dismissive at all.
Tovec, stop being a jerk. You just removed the context from my comment, and then pretended I had said something dismissive that didn't have the reasons for my comment. Not cool man. You want to argue about what I say, then quote what I say, and not just a snip of a section out of context like that.
But you dismiss that explosions which fill the 5x5x5 square are not the same as a sword swing which at best does a 5ftx5ftx1inch space.
I am not dismissing it, I am saying I never claimed it is identical, just similar. Again, you first claimed I never said it was identical, and then the very next sentence talked about how it was not the same. You realize the definition of identical is the same, right? I am waiting for you to explain why the difference you note is meaningful for this discussion?
And yet when I, and others, give those reasons why we don't object to one but object to another you dismiss them saying our reasons are, "inconsequential." I have to doubt you want our reasons.
WHAT reasons? All you are saying is they are not the same...not why the differences are meaningful for this discussion.
The problem is the following:
The ability does not work as actually described by Rodney and others.
The ability can never miss, not even on 1s.
The ability currently models (via other examples you yourself has given) explosions and splash effects that do a full square effect.
The ability works EVERY SINGLE ROUND, unlimited use.
None of that is inherently a problem. I don't know about "not work as described" as I don't know what you mean by that. But for the others, you seem to think the problem with those things is self-evident. They are not. You're skipping the most crucial step to your argument - why those things are meaningful. I've explained why an ability that does not miss, even on a 1, was present in 3e and nobody had a problem with it (with at least three types of things: 1) spells, 2) traps, 3) mundane splash attacks). There is nothing inherently bad about modeling a splash effect with a melee weapon, and in fact I think that is a good thing to add to the game. And there is nothing inherently bad about it working every round (you can also throw a splash weapon every round, for example - they are very cheap or even free, depending on the character and feats or classes they take).
You reply with the following, which are largely not the issues raised:
The ability works like fireballs, which are magic, limited use, and an explosion.
The ability works like magic missile, which is magic, specifically designed not to miss (and still can via other spells).
The ability works like alchemists fire, which is a splash weapon (which you find 'inconsequential'), requires an attack roll to hit a square, and oh yeah is limited use.
The spells were to demonstrate that it's not a new thing to the game to auto-hit on a miss. Traps do that as well. Just because those things are not identical, does not mean it's irrelevant to raise the issue that other things in the game also do damage on a miss.
As for the splash weapons, I disagree. They no more require an attack roll than this 5e fighter ability we're discussing (it also requires an attack roll). And it is no more limited use than this fighter ability (both are inexpensive weapons you buy with gold - anyone can afford oil or alchemist fire, particularly as you increase levels, and some classes could even make those splash weapons as an ability). And both do damage on a miss. It's a fair analogy to be making.
Which STILL doesn't take up a full 5x5x5 square - so no thanks. (Not to mention not addressing ANY of the other issues.)
Why would it have to take up a 5x5x5 square to be satisfactory (you want it to be MORE powerful?) and what other issues does it fail to address? Again, you seem to think we can all read your mind and figure out what you're thinking or something.