Dart+ Tunnel shouldn't have to wait another 20 years, nor can the Green Line upgrade to Metro. We shouldn't have to wait until the system is overloaded to do something, we should be anticipating the needs of the future and building to accomodate them before they become a problem. A lot of new housing and development is being built in areas served by the green line and it's guaranteed to get overwhelmed.
Orbital Luas should be moved forward, in the interests of suburban connectivity that doesn't require going through the city centre first, and for the sake of transit-oriented developments occurring on the outskirts of the city such as the City Edge project.
I feel like the Poolbeg Luas makes more sense to run down Pearse Street rather than a red line extension - you'd connect College Green, Trinity, GCD, Ringsend and the new SDZ in one fell swoop, and you wouldn't have to build a new Liffey Bridge - but I'm sure you guys have thought about all that already.
Run that bus down Fortfield Road anyway. Sure don't they all have driveways? Throw in a bike lane while you're at it