BiotechHedge,
What you are missing is that pathways, as you are calling them, are activated by mutations so are also ultimately mutation driven. I believe what you attempting to do is differentiate treatments via how far downstream in the signal transduction pathway an inhibitor is. Kinase inhbitors are downstream of ligand binging inhibtors, so are likey to be more broradly effcive. In the case of Curis, their hedgehog inhibitor is downstream to some degree.
I also find your blanket dismissal of ligand inhbitors amusing since Herceptin functions in that fashion, by blocking the HER2 receptor from binding its ligand.