Congratulations. This is what I call a bunch of whiners who are whining for the sake of whining and in their hurry to whine as much as possible showed how ignorant and completely oblivious they actually are and don't even realize it.
Erza's magic is based on storing weapons in a magical armory that she can access at any time. With other words this magic is as basic as they come, there is nothing special about it. However if she would just use regular weapons, that wouldn't make her much different from a regular soldier. The biggest advantage of her magic is that she can store a large variety of weapons and armors which she then can summon for specific situations. There is nothing hax of special about it, this is an ability as simple as they come, but highly efficient. That's the entire point of her magic and most of her weapons are all what you could expect. She used fire, water, lighting, speed, power etc. types before whenever it was needed. Using an armour or weapon that gives you an advantage over the magic of your opponent, that's the strongest point of her magic and there is nothing OP or hax about it. That's just you finding petty excuses to whine again.
The Morning Star armour she used before, nothing new. Not sure whether she used the water sword, but she used water equipment before and Lucy also has some kind of water whip, so nothing new there either. Wind weapon? Not sure if she used it before, but if you have fire, water etc. based weapons, logically there will be wind-based ones too, so nothing there either. It would have been more illogical if she didn't have it.
And still you people are whining. Erza took down Azir? It was a team effort. Erza was about to die, but then used a simple, but efficient tactic to let Bisca know where she was, Bisca then hit Azir with a powerful magic canon. Erza then took advantage of the situation to finish the job. What? The Spriggans were supposed to be as strong as the Wizard Saints? Laxus took down a Wizard Saint. And it was already implied that not all Spriggans are completely equal. And it was also shown that Makarov was highly underestimating the current power of some of the FT wizards. And did you expect that none of the Spriggans would be beaten or something? You people aren't even aware that your comments are far more ridiculous, illogical and stupid than you make this chapter out to be. This is also this typical attitude of VS threads where people only think there is some kind of universal ranking of all characters in existence and that a character that is ranked lower can never beat one that is ranked higher. Get a reality check, that's not how it works.
Erza used water and wind type based weapons. That sand is weak to water, is something that is used in many series. She intentionally used weapons she knew would be advantageous against Azir. That's how her magic works, it's called being prepared and fighting intelligent. Agreed her Nakagami armour can be considered hax, but that's pretty much the only one and in this chapter she only used it to deal the final blow after applying a simple, but effective tactic together with Bisca.
Do you how some of you people actually sound? "Oh no, Erza used a water weapon, how convenient! And this for a mage whose magic is centered around using a large variety of magical weapons and armors! I'm so in shock about this revelation that I have to whine as much as possible! And oh no she beat one of twelve powerful evil characters! How is that possible! I was convinced that all the heroes would die and all the villains would be victorious! This makes no sense! And how could she have done that all alone, the fact that she received major help from another character I'm going to completely ignore!"
Every time I think people's comments can sink any lower, somehow some of you succeed in reaching a new level. The irony it is that you are whining about how bad the chapter is while your own comments are even less worth. Whining for the sake of whining, being oblivious to the fact that you're producing nonsensical BS. Then just shut up.