My idea for armor would be centered around breakpoints, which would allow both hybrid and specialized characters to shine.
Short explanation would be that armor skills/spells with status effects apply a status effect, depending on the penetration of the attack, much like how we have shocked -> stunned or chilled -> frozen right now.
So, let's pretend we have a big bad warrior with 100 phys armor but 25 magic armor. This player would easily be targeted by status effect from spell casters and receive more damage from this type for obvious reasons. Naturally it would be the opposite for characters with how magic armor, but low phys armor.
Naturally such a system wouldn't have a degrading armor like right now, but rather have a static reduction to damage of some sort. Hybrids would be viable, since they would be able to target the weakest armor to increase their damage and cc potential, while specialized classes would be stronger against targets lacking in their preferred type.