I've always thought that German transport was generally excellent when I'm over there, but then I'm from Dublin :)
Light rail in Dublin is quite good, but coverage isn’t great. I used DART a few times, and it wasn’t a nice experience - long waits and less than ideal trains. I traveled by rail between Dublin and Cork, however, and it was quite good - modern and comfortable, and relatively fast (Ireland is small and fast rail feels like overkill)
Not sure I'd say that; a modern TVG/ICE-type service could do Dublin to Cork in less than an hour, vs 2.5 hours for the current service. That would be a game changer.
There are vague plans for such a service, and more solid plans for upgrading to 200km/h (the trains already support this but the line would need upgrading).
What germany does horribly is ISP infra. It just sucks ass.
Also, some gas and electricity pipes running south wouldn't hurt, but it's too late...