I wrote to the room coordinator at MOC in mid-June with my preferences for room location for our upcoming August reservation. I didn't hear anything back from her until last week, which was also when I got the Preferences email asking for my preferences. Both emails arrived on the same day (one from her, noting my preferences and the standard Preferences email, which I also filled out.) I don't know yet where we'll end up, so I don't know if my email helped or not.
Like you, we are multi-week owners at Grande Vista. I used to get my room preferences there every time, but for the last 5 years or so we don't get anything close to our preferred view/location. I wonder why that is? It seems that when they changed the Preferences email to be so generic, we stopped getting what we wanted. At check-in, I always express my disappointment and ask if there is a villa in our preferred location. So far there always is, but we have to wait for it to be cleaned. Given that we usually arrive around 1:00, this means we always end up waiting until after 4:00 for our villa. But at least we get our preferred location.