I was playing in a competitive Pixelmon server with a level 100 Aegislash that was a relaxed nature with 100% ivs across the board with 252 evs in attack and HP. I was in the training area fighting a level 80 garchomp with 31 ivs across the board with a natural nature along with no evs. I used sacred sword and it only did 27% to the Garchomp. I ran the calcs and at minimum, sacred sword from 252 attack 31 iv level 100 Aegislash does 47% to level 80 0hp 0def garchomp. I then ran the calcs for aegislash shield form and found that it does 25-29.6%. So, Aegislash stats do not change to blade form despite changing appearance in battle.

Greetings,

It does seem that it's not switching stats when it takes the new form.

Thanks!