It was horrible.
It was horrible because it applied to literally everything, even machine guns. There are times where something took a LMG spray to the optic and instantly exploded without actual damage because of hull break.
The only way a mechanic like that would be balanced acceptably is if it applied exclusively to certain ultra high energy weapons (FV4005, LOSAT and similar) and was not just limited to “light armor” like before. In hull break era your example would have survived because of the MBT chassis it is built on.