It isn't a great resolution for media, it is great for movies, but most other media is 16:9 and some is still 4:3. Do you really only watch movies on your phone? And even with movies you don't lose much when cropping to 16:9. And in general it is too wide in landscape and too tall in portrait. Personally if given the choice I'd opt for 16:10, I can live with 16:9, but I wouldn't bother with 21:9.