but with substantial risks in terms of the counter-rotating LPT, variable-pitch fan blades
The LPT has NO stator stages, but rather alternating LH- and RH-rotation rotors. One set is attached to a central hub/shaft, the other set to a rotating case. Very imaginative in that neither "rotor" has to turn very fast, thus direct drive to the external fan blades.
But the blades are each attached to this outer case system, with a complex flex-shaft system supposedly keeping them all synchronized. Every flex shaft system I've worked on has left me unimpressed regarding airline-standard reliability; and unless some sturdier wizardry is on the horizon, I doubt it could pass muster.
TSFC at cruise - IIRC - was under 0.25.