I was in Limerick yesterday, and after your post I decided to have a good look on both sides of the dual carraigeway from and to Ennis.
There was some litter (ie drinks cans, crisp packets, sweet wrappers etc) along both sides of the road, but nothing to the extent I thought you were talking about. I didn't see any rubbish bags lying around, just the small amount of littering you would see in any city, town or village at the moment.
I also used the ring roads, and travelled through and back the city, and I really wouldnt have a problem with the litter there.
In my opinion, the litter problem has improved in recent years, and is actually better than it used to.
I agree with your statement about the various councils, as too many cooks really do spoil the broth, but I think that there isnt really a litter problem in Limerick, and it is just the level that you do unfortunatly see around the country.