This is why deshield is overpowered and one of the things that makes invoker incredibly hard to kill.

Not overpowered...it's completely logical...just like my suggestion.

If it had no lag, then it might be overpowered. Warriors get two specs,
so that can be utilized to really screw an invoker over.

I could argue that every Legacy is overpowered...that any dam roll
above 40 is overpowered...etc, etc. But they're not. They are logical.

How about things like tigerclaw, deafen, and worldbind? Any of those
can make over half the classes in the game nearly powerless...and you
are calling "deshield" and "spell renewal" overpowered?

Bizarro I'm helping!