Untrained warriors are WS2 (skeletons, men-at-arms, flagellants, goblins), experimented warriors are W3 (halberdiers, orcs, knights errant, saurus warrios), elites are WS4 (temple guard, knights of the realm, greatswords), and extraordinary warriors are WS5 or more (melee combat heroes, elf elites, dwarf elites, chaos warriors). The WS statline across the armies is very satisfying. No need to change anything.
I wouldn't allow heavy armor to be available to all melee combat state troops. Heavy armor should remain a specific niche in our army. Such armor is very costly to produce, and few armies have core infantry costing less than 10 points wearing heavy armor (stormvermin, dwarfs). At best, I would allow one unit of swordsmen, spearmen or halberdiers to be upgraded into a Honor Regiment (heavy armor) for 2 points per model.