As far as I recall, the section south of Sandyford is fully segregated from road crossings, so probably a better candidate for Metro than Charlemont-Sandyford.
No it's not. Quite the opposite: there are several road crossings between Sandyford and Bride's Glen. Its also quite limited in terms of curvature and line speed.
The whole thing is a resurrection of an old, discarded plan to upgrade the Green line to Metro standard South of Beechwood. The construction of the Cross-city Luas line makes that plan a bit of a nonsense, yet it gets resurrected. That's what happens when politicians are let loose on investment decisions.
Ross is a disaster.