There is no technical distinction between light and heavy armor, but there is a statistical one. Lighter armor has a lower evasion penalty and has a lower AC boost. Heavy armor has a severe evasion penalty but in return gives you a large boost to AC.
In reading guides for different types of characters, I've seen some that are focused on evasion and others that are focused on AC. Nowhere does it give any guidelines, however, to determine which is more effective than the other.
What kinds of characters should be focusing on increasing their evasion vs. AC? Does heavier armor inhibit movement or slow down your attack speed or have any other effects?
As a case study, if I wanted to play a Minotaur Berserker, what thought process should I go through when determining whether to stick to leather armor vs. putting on the plate mail I just found?