Supplies?

[NTJedi]

DominionsFAN said:
The AI gonna build castles as we know, ...

Yes, but hopefully the AI has been developed to know where on building these castles and staff/guard correctly. If it just randomly selects provinces leaving few or little units it will be more of an AI weakness.
Each province should be considered for a castle based on the following variables:
Bottleneck province ( 2 or 3 connecting provinces )
-castles built here are important for defensive purposes
Highway province ( 7 or more connecting provinces )
-castles built here are important for offensive purposes
Gold income for the province ?
How many magic sites in the province ?
How much gem income for the province ?
Total population should be considered, but not as important as the other variables.

DominionsFAN said:
and if this is true [probably the castle type what you can build will depend on the size of the province?] the AI can handle the castle building very well.

Yes it would be nice if certain provinces couldn't have castles for most nations. For example only a few nations can build a castle type in the swamp... such as C'tis.