All fist weapons have a lot lower base critical than the other weapon types. In fact, a dagger weapon has a base critical of 12, a sword has a base critical of 8 and a fist has a base critical of 4. This is consistent across Chronicles, not just C3.
If any of you have access to later Chronicles I’d like to see some information from later balance changes, e.g. what’s the actual critical rate of fist weapons in later Chronicles with the same buffs.