True, and true.
Music licensing was a big problem there. But ultimately, the ball was dropped.
The biggest problem with NE, as far as DVD release was concerned, was that there was so much incredible music that was used. And a lot of it was integral to the show (hard to explain if you haven't seen the shows).
And those hardcore fans, like myself, can quickly point out where something was substituted. Luckily, certain episodes where it played a huge part in a scene have been preserved. Most notably in season 4 where a certain Enya tune was used to close out an episode (and whether you like Enya, or not, it WAS integral), and the show where Mike the bubble man left, which ended with a rather plaintive Chieftains tune.
A lot of long time fans are quite pissed, but for the most part, the tunes that really need to be there, are.