So this is kind of why I'm still kind of on the fence but leaning towards ban. While there still isn't a real definition of Uber, it's still something to think about.
Quoting from
http://www.smogon.com/forums/threads/the-definition-of-uber.3460453/
Well, can it sweep with little effort? No. The only thing that can really sweep is gimmicky autotomize WP sets and the SD set, neither of which are particularly easy to set up and sweep with.
Can it wall and stall out a significant portion of the metagame? No. While it can beat a lot of the metagame 1v1 and can come in on numerous threats, I don't think its staying power is really that high.
While Aegislash is a freaking amazing offensive pivot, I wouldn't call wear and tear via shadow ball a support characteristic.
Is Aegislash a dominating force and does it dictate playstyles to be majorly centralizing? Kind of. While a lot of the pokemon in the current meta would still be great with Aegislash gone, I can't help but think the ground-based meta with the likes of Hippowdon, Garchomp, Gliscor, and Landorus has been influenced heavily by Aegislash.
But here's my main issue with Aegislash:
The risk/reward ratio to
using Aegislash is way too low. Aegislash, despite very many things that can threaten it in the meta, is the most used pokemon and still
one of the most consistent. It's
ridiculously easy to use, will always likely do more than one pokemon's worth of work. It definitely doesn't have hard stops and beats many pokemon 1v1. The question really becomes, why
wouldn't you use Aegislash? It's a great stand-alone mon, requires literally no support, and does wonders for any team.
Aegislash is one of those "super-safe picks", as it'll never be dead weight for any team and will put in its work. It doesn't have the risk associated with using other pokemon, for example there are many cases where Mega Tyranitar will get to do absolutely nothing, same with Azumarill, or Heatran, or Chansey, or any other pokemon.
King's Shield is just icing on the cake, the reward from getting one prediction is ridiculous.