Most Metro announcements are deafeningly loud, mostly unintelligible, overly redundant, often not pertinent to most riders, and simply occur way to often (becoming nonsensical background noise). Please improve the station and train PA systems, and limit announcements only to those that are truly of importance/use (e.g., if I'm leaving Ballston station, I do not need my ears blasted about an elevator outage at Van Ness).
I just returned from two weeks in London, using the Underground/Tube for most of my travels within the city. The system operated amazingly smoothly, and one aspect that I immediately took note of was the lack of unnecessary announcements and PA systems that were clear and at a reasonable volume. I've got to believe Metro can do the same, if they want to.