@Meneth:
An Ireland with 32 provinces but only 2-3 holdings per province (with only 1 built in 1066!) is actually a novel and quite intriguing idea. If you look at how Ireland was governed in the middle ages - or rather, how it had pretty much no government at all - such an extremely low density of holdings would fit the land and its historical theme VERY well. Ireland in 1066 had almost no cities and certainly no bishoprics. It's hard to imagine it if you are familiar with Ireland today but back then it was not an agricultural country at all, at least not in the sense that they raised a lot of crops. Ireland was a country mostly of pastoralists, with very little settled life going on. Whose traditional legal code referred to calfs and female slaves as the unit of measurement for the severity of a fine. Warfare revolved around the capture of cattle and slaves, and the imposition of tribute, not around territorial conquest. They didn't even have villages, instead people lived in the sort of settlements you only see in Africa nowadays: A bunch of huts around a kraal type cattle pen. One extended family per settlement, more or less. The CK2 typical castle + bishopric + city province is in this context a very weird and alien construct.
In that spirit it's actually an exciting idea to fill Ireland with lots of 1-holding provinces with at best 1 extra slot for improvement except maybe in the Dublin/Meath area where historically the social development towards settled life, agricultural lifestyle and feudalism took the most roots.
There used to be some mods for Ireland back in 1.05/1.06, made by Irish modders, and all of them focused on making the land less centralized, less feudal and more anarchic. A regular feature of those mods was that Irish duke and king titles would by default dissolve upon the death of the holder. In a country full of 1-holding provinces this actually sounds like a perfect way to represent the anarchic, thinly settled and non-feudal nature of Ireland.
Also if you only put 1-2 holdings into the provinces it is probably even less CPU load than with the SWMH map as it is now. CPU load depends on the number of courts, i.e. the number of feudal rulers in existence at any one time, since events and diplomacy revolve almost entirely around the rulers. Less holdings = less courts = less CPU load even if there are more provinces.
Lots more provinces could do with lower holding caps. I think having the Lebanon / Holy land region fractured into many provinces is cool, but I share Calahir's sentiment that this must not go together with high holding numbers. The holy land region is much too rich otherwise, and k_jerusalem definitely has to be cut down from its 80 or so holdings to a more reasonable 50.