After doing a search which turned up nothing, I'm wondering if it's at all possible to retrain, say, Polybian Hastati or Princepes as Cohors Reformata. Would this require an insane amount of scripting? or is it Hardcoded and untouchable? I mean, i find it INCREDIBLY frustrating when i'm forced to give up and phase out very experienced units and struggle to bring new ones up to speed before my old unretrainable legions fall apart.

If this is impossible, then is it possible to mod how fast units gain experience, or have the building itself give the soldiers some to start with?

TY in advance for putting up with me