Following the census we have just submitted, it is likely the Dail numbers will increase by a significant amount - between 169 to 179 or so.
There is a requirement in the constitution stipulating the number to be at least one TD per 30,000 of the population. The numbers will be swelled by the Ukraine refugees, as the number is defined by population, not voters.
Now the number of legislators required should not be proportional to population - well not a simple proportion, because as the population grows, we do not need more TDs, otherwise countries like Germany, or the EU, would have huge parliaments/assemblies.
So how should the number of TDs be arrived at? Let us assume 160 for the moment - currently 160.
Well we need a Taoiseach, so that is one. We need ministers to run departments, and that is capped at 15. We have Junior ministers, again about 15, but that has grown as needs of coalitions mean an extra one or two are needed to balance political numbers. Add a few committee chairmen and deputies - say another 15. So we get to the number of TDs on the Gov payroll getting up to 40.
So if the Gov has 40 TDs in some form of executive roll, then that means 50% of Gov TDs are considered able to carry out those functions. Now given anyone can run for the Dail, and any of those could be elected with the only stipulation that they get enough popular support (votes), they any elected TD could be of any level of ability. So if 50% of Gov TDs are selected to serve in the executive and are selected on merit (generally true, but not always) then 160 TDs should be enough to get a good set of individuals with sufficient abilities to run the country.
To limit the number to 160 would require a constitutional amendment. Would it be worth it?
https://www.irishtimes.com/news/politics/census-2016-shows-the-number-of-tds-breaches-constitution-1.2722184