The main reason I don't use eq while tracking vocals is that as soon as I do, it's 100% certain the singer is gonna wanna punch-in one line two weeks later, and by that time, I'll have forgotten what eq I used on the basic track. That eliminates one big variable, and just leaves previous mic selection and placement.
Of course after two weeks have gone by, the singer has probably changed the emotion they bring to the song, so the punch-in never works, and I end up retracking the whole damn vocal anyway.