The DT currently supports title searches, so if "someone" can have an idea of what is in a title, why not the more obvious what someone thinks is in the first line or what someone thinks is in the chorus. This is an end-user's idea not a developer's idea (in my 35+ years as systems programmer, systems designer and systems manager I've always designed from the end-user's perspective not the ease of implementation). To quote my example above, if I was looking for a song that I thought had barley in the chorus I'd prefer to look through the 15 songs with barley in the chorus rather than 60 songs with barley in the song. I do listen to songs and I know what a first line is and what a chorus is, usually more reliably than what a title is; if I didn't find it from what I thought was in the first line or chorus, then I'd be willing to look at the list from a full-text search.
Saying that full-text search is the first resort is not the best service you can give a user (certainly not this user).
As regards the delivery method I have no problems with whatever system (I use the current download version all the time at home) is used to do that (unless I had to implement the system). My problems would be with the data organisation. Lumping everything into the text is not good (Try searching for Irish Ways And Irish Laws if all you know is that the song had the word laws in it -see what a full-text search gets you then).