At first glance it looks like a very threatening team, but there are definitely areas to be improved.
Your Klefki may want to carry Foul Play, you have nothing to take on Pokemon that are going to try and set up and sweep.
I think you should consider changing Aegislash's Nature to Brave as this reduces his Speed, you want to be as slow as possible so that your opponent attacks you in Shield Form and then you attack in Blade Form. Which is why I think you should change Shadow Sneak out for Shadow Claw, Shadow Sneak without Swords Dance will just leave you so vulnerable in Blade Form.
The only other thing I will say is looking at your team Stealth Rocks can hinder and also dent a lot of your Pokemon, especially Talonflame & Gyarados and Greninja won't like taking Stealth Rocks on top of the Life Orb damage. Ideally I would say swap out Greninja for Starmie, but one does not simply change a Shiny Greninja for anything so it looks as if you're just going to have to keep it alive and rely on Taunt.
Also, Bulk Up and U-Turn on the same set seems a bit of a waste, because you don't have a Rapid Spinner or a Defogger I would go with Roost.
...Diggersbytho
