Honestly I don't know if a physical aegislash could work in this metagame with all the intimidate spam and bisharp around. A mixed set with weakness policy can work pretty decently with just the proper timing and prediction. Most aegislash sets are probably gonna be working around a mixed set with either shadow ball, flash cannon/sacred sword (for kang, heatran, hydreigon, t-tar) and shadow sneak. As for other options, king shield is self explanatory, substitute still works great, as well as wide guard to stop heat waves, surf, and earthquakes.
Edit: I think people will start seeing more aegislash sets like this that is designated to tank special hits, retaliate with shadow ball and hopefully nab a +2 boost to its stats.
Collin Heiner's Aegislash Set @ Weakness Policy
Ability: Stance Change
EVs: 252 HP / 4 Atk / 4 Def / 92 SpA / 156 SpD
Quiet Nature
IVs: 0 Spe
– Shadow Ball
– Sacred Sword/Flash Cannon/Shadow Sneak
– Substitute/Wide Guard
– King’s Shield
Edit: I think people will start seeing more aegislash sets like this that is designated to tank special hits, retaliate with shadow ball and hopefully nab a +2 boost to its stats.
Collin Heiner's Aegislash Set @ Weakness Policy
Ability: Stance Change
EVs: 252 HP / 4 Atk / 4 Def / 92 SpA / 156 SpD
Quiet Nature
IVs: 0 Spe
– Shadow Ball
– Sacred Sword/Flash Cannon/Shadow Sneak
– Substitute/Wide Guard
– King’s Shield