One of the main objectives to make the Hollow Crown was to make an epic, large scale production of Shakespeare for TV with on location filming and authentic sets like in quality film/cinema. In addition to making Hollow Crown a high quality production, the BBC wanted it to be accessible to mainstream audiences. Some Shakespeare lovers had a problem with that, while others felt that this goal was very well realized for the small screen with all three plays. Some of this was achieved with the language not being too "Shakespearean" along with cutting down the plays for time and for the large sweeping battle and landscape scenes. So it really depends on what standard you're measuring each play by. Some people responded more to the traditionalist style of Richard II, while others found Henry IV and V more accessible and engaging.
If you feel so inclined, you can read the rest here.