^Hogwarts Express is both a screen-based attraction and a transportation system--not to mention a way to ensure that Potter fans buy a two-park ticket.
As a Potter fan, I think HE is moderately fun (c-ticket level), but they could could have encased it in a tunnel with real props/scenery (incorporating some projection mapping or embedded media screens), left the windows open, kept the frosted door shadow effect (which I think is really cool), and it would have been a much better attraction (though I know it would have been significantly more expensive). I think you are just sitting too close to them for the faux-window effect to even remotely work (if you're sitting right by it not only can you easily see the edges of the screen but also the "screen door effect" created by the low pixel density of the video).
I like what Disney is seemingly starting to do with newer rides Shanghai Tron and POTC, and now (based on reports) the Navi River Adventure at Pandora, embedding/incorporating projection mapping/media screens into practical sets to enhance the immersiveness rather than have them act as the main focal point. Even Flight of Passage will have the Banshees that you're riding on rather than just plain benches/seats.