Monster INT is a helpful stat
Working with OD&D sources, one of the things I miss is an intelligence stat for monsters. It’s one of the few things which causes me to reach for my 1e Monster Manual or OSRIC. As a DM, I’ve always found those intelligence scores to be important when controlling monsters. Maybe this is one of those things a 0e DM has to decide for himself—my stirges are cunningly intelligent, or the traumatic death of wights have destroyed their higher faculties in my game. That’s flavor, I suppose, and it messes with player expectations (which could be good or bad).