I think Phibsborough (Whitworth) is a much more sensible place for an interchange with the Maynooth line (though the article doesn't explicitly mention there will be one). It would be feasible for an interchange station between Metro and both Irish Rail lines, which is not possible at Drumcondra. Hopefully it will be an integrated station, and not two separate stations, as I believe would have been the case at Drumcondra.
It sounds like the entire Dublin Airport to Charlemont part will be underground, which solves a few problems. But surfacing at Charlemont? The only way I can see to do that is to CPO the entirity of Peter Place and knock it.
Detail seems lacking on what will happen to the Green Line. Cutting the middle out of it seems unworkable, as it would make current non-stop journeys require two changes. But does it have the capacity to run Metro an Luas? Will most of the Metro trains turn back at Stephen's Green, and only a few continue to Sandyford?
Is there a good reason for only making the Charlemont-Sandyford section Metro, and not Charlemont-Brides Glen? 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.