Personally, I still like the "homeland" concept. I actually would like to see legion troops ONLY recruitable in Italy. BUT, the campaign movement speed would have to be adjusted to some degree of normalcy. 4 or 5 years to walk across North Africa? Don't think so. So as long as the speed is rediculously slow, I stick with retraining the way it is. The Senate ordered me to take Domus Dulcis domus last night. I laughed out loud. My closest troops were in Tylis. It wasn't even possible to get there in that length of time. It's not like the AI builds roads or anything. OK, yeah, I know, "But what has Rome done for us?".
But even the Roman AI usually don't build roads.