Sorcery Ward ascendancy. Is it worth it?

It adds me 543 points barrier, but eliminates my armor and evasion to almost zero.
with no buff i have armor 31% and evasion 12%
with the buff - 20% armor and evasion 0

Based on what you have said it sounds like this is your first or second ascendancy and in that case no it's not worth it.

However, as the third or fourth ascendancy when you should have much more armour and evasion it could be worth it.

Due to the current mechanics of Armor and Evasion, Sorcery Ward scales better with evasion. People running Sorcery Ward are stacking Evasion and grabbing Beastil Skin: 100% evasion from chest armor.