True that it could be bettered but the same can probably be said for lots of routes throughout Ireland. In contrast (and on a positive note) I can get from Heuston to Sallins in about 16 minutes on certain services, try beating that by car!
I have never travelled by rail in the UK so I cannot comment on the comfort of the refurbished stock but, based on what others who have done have said previously on this forum, the 22ks are quite favorable and comfortable in comparison and I don't think having travelled one journey on them is enough to make the assumption that other stock is 'way better'.
Rail freight in the UK is increasing due to the fact that heavy industry is still prevalent there, something that is not the case here and is not the fault of IE. The refurbishment of the 071's, the presence of the DFDS and IWT liners, IE's new emphasis on attracting freight contracts among others would suggest that there is a future for rail freight in Ireland.
The fact that the NRA and the RPA are now, in essence, the same organisation would lead you to hope that there would be more cooperation in the future with regards to combining rail and road freight also.