But the area of recruitment should be smaller at start,
Well, it basically is: I've only gotten the Marian reforms once so far, but from what I recall, my first Marian legions ended up being recruited in Italy because, while the other regions now had MIC's, they were all level 1 MIC's, and Cohortes Reformatae required at least a level 3 or level 4 MIC, IIRC - that means that you aren't able to recruit Marian troops throughout the Empire for at least 3.5 years. -M