Even if the seat map were an indicator of load, which it is not, AA has sophisticated predictive software which recommends fare bucket (including award) decisions based on hundreds of data points to which none of us have access.
Just one example might be that AA anticipates the cancellation of some other flight which will create the need for seats on your flight. The last thing AA wants to have done is to have opened saver award space and then be forced to downgrade paying passengers.
Or, it's a big mistake because the software is imperfect.