While I think it's legitimate to write musical-centric fic as long as that's what it's labeled as (and thus to cast one of the actors as Enjolras if that's who's seen), I usually find it much more fulfilling to pull musical-only things into the Brick universe (like the Gavroche-Grantaire relationship). Mainly because the Brick universe is just so much fuller and deeper than the musical could ever hope to be, but the musical makes some interesting decisions that could be fun to play with.

I tend not to read much fic other than what's posted to the community, either, or fic by people who talk to me through reviews and seem like intelligent and nice individuals. RobertaWickham on ff.net (bobbiewickham on dreamwidth) writes some good stuff, including a canon-era Buffy crossover with Enjolras as a female slayer, that's worth checking out. Otherwise... yeah, otherwise I mainly read you guy's work and tinker about on my own.