I'll revise it. I was thinking that I'll have two types of light armor - concealable (for the shinobi, mostly) and non-concealable. One type each of medium and heavy armor.
Various descriptions of what each type could entail.
I worked up the encumbrance system today. Similar to Delta's "stones" system, I'm using vague "encumbrance units" and a PC can carry up to 1/2 their Str. score with no penalty. Up to Str. with modest penalties to speed. Up to double Str. at max, but severe penalties.
A full backpack, a bag of loot, a large weapon, a bulky piece of normal gear, light armor - all count as one encumbrance unit.
Medium armor counts as 2 EU. Heavy armor is 4 EU.
Medium weapons are only 1/2 EU, and Small weapons are 1/4 EU.
Actually, thinking about it now, that might be broken for PCs with 18 Str and overly severe for PCs with 3 Str. Maybe I'll adjust the numbers to base 10, with bonuses and penalties for high/low Str similar to BX D&D, like this: