I disagree on Erza's wins, Basically she is built around "there is an armor for that". The only way to counter that is preparing for every armor she has. If she shows all of her armors off regularly she will encounter more people who want to take her out and might succeed in doing so. If she has a couple of armors that are so rare as her last toy, then people with similar magic (exquip is a certain style of magic and Erza is not the only one, just the best) will hunt her down for her collection.

So it makes sense for her to keep her stuff hidden as best as she can and not show it off.

Second, her latest armor might have side effects and restrictionscoming along with the power.

I think she deserved what happened in this arc. Yes she did impossible things, but then again, she is one of the strongest mages on the damn planet. FT (with the TI group) is the strongest guild out there... Erza is the 3rd (?) strongest in the guild and there you go, she is one of the strongest wizards on the planet there, and maybe could have taken jura on...