The UNESCO website is not particularly clear on which sites are incorporated by this proposal. Only Dún Aengus (on the Aran Islands) is specifically mentioned.
I visited Staigue Fort in Western Kerry in February 2009. It was a great stop on a lovely drive on the Ring of Kerry.
The fort itself was small but very impressive, built of thick dry-stone walls and commanded a nice view of the valley down to the Atlantic. It is circular with a very small entrance at the front and a few stone chambers in the wall. The stones inside of the walls have been piled up to create stairs to enable you to get to the top of the walls. I climbed up and was surprised by how big the drop was on the other side; it certainly would have taken a lot of effort to get inside if it was being defended. The fort was a fair way of the main road and I was the only soul here, apart from one sheep. The out of the way charm of the place made it a worthwhile stop.
I am not sure if these sites would be put forward as the Irish tentative list is pretty old now and nothing much has happened with it for a long time. They could be an interesting addition, similar in character to the Temples of Malta, though nowhere near as old. From what I can gather Dún Aengus is a very impressive site, but perhaps not strong enough to make it on the list by itself. Putting the western stone forts togther seems like a logical way of making it a more viable candidate for inscription.