Elenium is plenty dark, but the main characters are basically charmed and borderline invulnerable. Except Kurik =| It's a very tame type of fantasy overall, and the Shannara books are substantially "darker" with more death and chase scenes and what not built in, while the Sparhawk books always have the plodding towards victory feeling. Especially once Sparhawk gets Bhelliom hah.
There's not really any teenager type antics going on, and now that GoT has made sure that the adult version of fantasy needs to have tits/swearing, it would be difficult to market it without substantially changing the tone, I think. It's fantasy for the DnD/Tabletop wargamer. Doesn't mean I wouldn't watch the shit out of it!