You're still not comparing like with like. Pearse puts another 10 minutes on Longford services exactly the same as for Dundalk. The morning service is over two hours from Edgeworthstown to Pearse, the evening one is as long as it requires a change at Connolly. And if you're comparing Edgeworthstown, you should be comparing Drogheda. The extra 20 minutes at Connolly isn't really a choice. If you don't wait, you will definitely spend about 40 minutes standing and you stand a good chance of spending over an hour standing. Try doing that 5 times a week.
My point is that they should not be using these trains on 2 hour runs (Some of the Longford trains come from Bray so end-to-end you are not far off three hours actually). When Irish Rail put in the second 22K order they actually stated the reason for the order was that they would use the 22K from any runs longer than 1 hour so at the time they acknowledged themselves that the 29K didn't offer sufficient passenger comfort for this duration of a run.
Maybe it is something in the air on Longford, because this issue has massively pissed off any of the commuters I've talked to. If everyone on the Dundalk route is so happy with the service, that's their own business, but I know a couple of people on that line (around Drogheda and Rush) who have switched to buses as they are cheaper, more comfortable and faster.