Yeah, against protected HW groups you may be slightly behind in a frontal fight, but with the extra mobility from a unit of six, and the versatility to be able to fight different types of units more efficiently than protected (protected impact foot, pike, protected off sp/def sp etc..), i find them just better versatility wise, and its only like 12 points to upgrade a unit of six protected to six armoured... even if you have 5 units of six like i do in mine, you'll still only be getting sixty points, one unit of cav or two units of six LF crossbowmen, which wont help you against the pikes, but may ward the shooting decently.
I run my warring states as:
3x4 units of 4 armored drilled average swords/crossbow cav
3x4 units of 4 proteced undrilled average sword/bow cav (tribal)
5x6 units of armored medium foot heavy wep front/x-bow back, all drilled average
1x6 unit of armoured offensive spear
Inspired commander and two troop commanders.
So really, for me, if i changed the foot to protected i could only get two units of light foot really, which in this case wouldnt really do much to help the army as they're pretty warded against shooting as is, due to the inspired commander and the fact that i use the tribal cav as rear support for the medium foot until the impact phase is over, and things are going smoothly (or if people are getting around the flanks). It might bulk the army out and make the break point higher, but i'd prefer to have that extra edge in the main melee than lose slower if the main melee breaks through my ranks.
It all depends on the army, an army with huge amounts of protected heavy weapons could still do well, but in the warring states where you can only have 32 bases of non-poor medium foot, i'd much rather have them armored.
