I don't see how it'd get banned in tournaments since the real competitive battlers are much smarter than the AI. :p Still a funny read though.
Because Pokemon with high stats and broken combos get banned early competitive play. Just like Speed Boost Blaziken did in Gen 5. Garchomp in Gen 4. Moody got banned because of how outrageous it can get, Drizzle/Swim got banned because of the over use of it and because of how flexible rain weather was for other scenarios.
Aegislash could become banned early in due to its outrageously high Attack and Defense with no set draw backs until enough counters appear to have him taken off. I mean before he attacks he can have insanely high Attack and he has Priority Defense which changes him back to his defense form which has almost as much Defense as it has Attack. Think Shuckle being able to freely change his Defense Stat with Attack at any time without wasting a turn to do so using a move and being able to still attack with the switch activated.
This is all for Fan tournaments though. He'd never get banned for an official tournament. The only things banned from official tournaments are Event Legends, Box Legends (Ho-oh, Lugia, Rayquaza, Kyogre, Groudon, Dialga, Palkia, Giratina, Kyurem, Reshiram, Zekrom), Mewtwo, Chatot, Skydrop, Dark Void, and the Enigma Stone. Zygarde, Xerneas, and Yveltal are most likely the only three that will officially be banned. They may Ban Mega Evolutions since those are on par with or even surpass most of the banned legends.
I'm using Honedge, and loving him. I can't say mine seems over powered as he's the weakest member on my team thus far.