Having a black list would be an admission of their prudishness though.
Not really. It would be a sane way of specifying which domains they won't allow to be registered. A LOT of ccTLD (and gTLD) registries have block / reserved lists. People may not like the fact that they cannot register domains on those lists, but it's a fair system, as nobody can register them
The main issue with the IEDR's current system is that there is far too much subjectivity.
For example, the IEDR have a geographic rule. However they do not specify anywhere in their rules what exactly constitutes Ireland.
From my perspective subjectivity equates with headaches and increases the cost of selling IE domains. If we have to play email ping pong with the registry and the registrants then it makes the IE ccTLD a lot more expensive to offer.
With a .eu, for example, the likelihood of there being any human intervention in the process is minimal. Close to 100% of registrations get processed automatically without any delays