I didn't care for most of the Glee renditions of the Beatles songs, but when it comes to the Beatles, I guess maybe you had to have been there at the time to appreciate what they accomplished. If you go back to the pre-Beatles days and look at rock music, it had a good beat, but for the most part it was a lot of repitition. You can look at some old songs, like the Chuck Berry songs, you'll recognize the same tune a lot of times, but he just used different lyrics. The Beatles transformed the genre.
The went through a series of reinventing themselves. They started out with a basic rock format, but then they grew and diversified. Even though some of it may have been drug induced, the used a variety of musical instruments and different influences, like Eastern music, and all the other groups of that time ended up doing a lot of the same things to compete with them. It was a fun time, when you didn't know what they were going to come out with next.