> If we want to test these beasts in logic, we should probably start using actual formalized logic, rather than English.

Why? Do you use formalized logic when discussing with other people about topics that involve logic? You know, a logic riddle or a philosophical question can be understood and processed even if the only tool you have is your native language. Formalized logic is a big prerequisite that basically cuts out the vast majority of Earth population (just like coding). Now, if you mean that in BENCHMARKS they should use formalized logic syntax, probably yes. But in addition to plain language tests.