So this has been bugging me since the game was released. What we have is two elemental wheels in this game.
Wind --strong against--> Fire --strong against--> Ice --strong against--> Wind
Water --strong against--> Earth --strong against--> Lightning --strong against--> Water
How does this make a lick of sense? Wind puts out fire? Maybe if that fire was a candle or a cub scout's feeble merit badge attempt, but as far as real fires go, wind usually exasperates the problem by giving fire mobility.
Water erodes earth? Sure does, see: the Grand Canyon, etc. But do you know what water could be doing instead of taking thousands of years to cause significant changes to a landscape? Putting out fires. There's more pressing matters for water to attend to.
The (theoretical) Wind --strong against--> Earth link has always been the weakest connection in my mind, looking back at FFXI, but I always thought of it as being similar to the reasons Flying type Pokemon are strong against Ground type Pokemon.
You can't even argue that one wheel represents astral elements and the other umbral elements, because when was the last time you thought of lightning as a "dark" element, it's got "light" in the name for pete's sake.
It's confusing for everyone who's played another Final Fantasy game, especially FFXI veterans. I see a lot of arguing going on (especially in that Garuda thread holy crap guys) about elements and their strengths/weaknesses (and that somehow translates into jobs being completely excluded from the fight, give me a friggen break) with people not knowing the way the elemental wheel works in this game and why they're confused. They're confused because it's a messed up elemental wheel.
tl;dr The elemental wheel is messed up and is confusing a boatload of players by having wind somehow strong against fire. It should be fixed to be
Wind --strong against--> Earth --strong against--> Lightning --strong against--> Water --strong against--> Fire --strong against--> Ice --strong against--> Wind
And before you go "Well water isn't even included in the game anymore" I can guarantee that it's not gone permanently, and that it'll be returning either when they readjust THM and CON or when they add a new mage class (probably Arcanist).