If LibQuixote-2.0 provides the functionality you require, you may wish to consider if your users are likely to be using other addons that use this library. Although the efficiency of your own addon may improve by using a library with a smaller footprint (or by doing the work yourself in your addon), those gains may not be practical if the user is already running LibQuixote-2.0 anyway.
That said, I'm unaware of any other libraries that provide the same functionality as LibQuixote-2.0 without "the party quest sharing stuff."
I can't think of too many addons that would benefit from anything LibQuixote has to offer, and I can't think of much reason for anyone to use more than one of them, so if you're not interested in the comm features, you'd probably be better off just writing your own code for the other stuff and not using the lib.
LibQuixote-2.0 just tries to whisper its version to any new member in party/raid. In battleground, it fails miserably to whisper to cross-realm players, hence printing "No player named "Foo" is playing" (or the like). Since I edited the library to disable this behavior in raids, this kind of spam stopped.