Of course it sounds nice in theory, there's no solid metagame yet so anything here is bound to just be theory.
Rock type isn't the most present type in OU, aside fron Tyranitar and Terrakion. Tyranitar is going to put a stop to it, pretty much, but I wouldn't want to switch a Terrakion into a Brave bird (I calculated choice band bb as a 2hko I think). Can't see Tyrantrum, Aurorus or Carbink being hugely popular options. Bulky waters will be dented, but they deal with Talonflame well, yeah. Aside from that (and Heatran), that leaves quite a large portion of Pokémon that can be smashed by Talonflame, it's ability really allows it to act as a premier revenge killer.