Since I moved to Dublin last year, I've spent a lot of time thinking about public transport. In Dublin the vehicular traffic is far too easily routed through the centre. The M50 motorway around the outside is an excellent bypass for cars from the west and south to get to the airport - or vice-versa, but an annoying tax on that route encourages people to drive right through the middle of town instead. I never drive it, although I would do it more often if I could pay cash, rather than having to remember to go to the website afterwards or get stung for usurious penalties.
The Luas have some promise, but won't realise it until they have some more useful routes on the North Side, and some kind of ring route around the North Circular from Spencer Dock to Heuston and then around the Grand Canal and maybe to Irishtown or something. That kind of coverage would bring it up closer to halfway to the standards of somewhere like Zurich, where you can actually trust the light rail to deliver you within a reasonably short walk from your destination, possibly switching a time or two in your journey without usually having to spend more than five minutes waiting.
The DART up and down the coast is OK, but it gets unreliable in the middle of the city, and getting between Connolly and Heuston involves way too much walking and waiting for it to be in any way a convenient thing for any mobility-challenged tourists to use. It should probably include Maynooth and Drogheda within the actual electrified DART too, rather than having them as limited commuter rail services.
And as for cycling! I find the one-way system terrifying on a bike - I think you probably really have to know what you're doing and end up travelling a long way round because you're routed with the cars, or walking the bike with the pedestrians.
I can walk OK though, usually, and when I can't there's Hailo, so it'll be grand.