I like the thoughts behind the ideas, but I fear they would limit the game too much.
I already had problems with the slot system, as for example you weren't able to be a dedicated crossbowman (or even archer) but wield a shield and a 1hd weapon as sidearms. I liked the idea of dedicated crossbowmen being slightly inferior to dedicated archers over range, but making this up with increased melee capabilities. You know what I mean?
Limiting the items the way you mentioned it would either limit certain builds to certain inferior equipment, or using certain equipment would limit the choice of builds for it.
I as pikeman was shocked by your suggested 8PS requirement value. So I need to have 24 strength to wield my weapon? Currently I am 18/21, which is rather versatile and balanced (I can also use a halberd or be a hoplite, that's why I like polearms so much), with your suggestion I would be 24/15, and I doubt any other pikeman would go 27/12 or 30/9. With such high values people would always fullfill the minimum requirement and then push AGI, resulting in everyone running around with the same builds.
Formations are a nice idea, but I fear it's a bit half-baked. For example cavalry, in this game, will never benefit of any formation bonus. You can't have the classical charges of heavy cavalry into the enemy formation like in history, simply because in history knights were "OP", and one knight could make up for ten or more peasants. But in this game, everyone is supposed to have (about) the same value, so this can't work. Logical consequence is, that you must limit cav to "sneaky backstabbers", and that's why formations will always be useless for them.
Another thing are archers. Natural formations of archers are buffing themselves by default. The more archers you have at one place, the more they buff each other, it goes up exponentially, in difference to infantry for example, where they add up rather linearly. I know from RTS games that the more archers you have the less damage you will take in general, which can't be reached by any other unit combination. Infantry needs to be close to attack an enemy, so I would say four infantrymen attacking one enemy is the maximum possible in this game. But you can have 50 archers shooting one target, no problem! I wouldn't buff that further.
And the final thingare the infantry formations. You try to reward the same classes of infantry gathering together, but I am going around the forum for weeks now, preaching how game balance will never be achieved unless infantry stops sucking so hard concerning their "tactics" skill, which is an important part of the infantry role, unlike for the other classes, which don't need that so much. My point is, that the different infantry classes need to play together to achieve the maximum performance. No other class in the game is that dependant on tactics like infantry. While most of the times infantry is only suffering from cavalry and archers, if they play together they negate all counters, but still represent a counter to everything. Never mind how many lancer gather up, they will always suck against an equal number of pikemen (or even a few less). A high number of archers will do a little bit better against a high number of shielder than a small number of archers against a small number of shielders (they are buffing each other, remember? ^^), but still they will lose most likely. A good amount of two handers will lose against the same amount of archers, and one handers will lose against lancer.
But if you have a good formation (= lose formation, I don't talk of walking in line) of different infantry classes, with shieldmen at the front, pikemen at the flanks and the back, and two handers everywhere between them, there is nothing that is particularly good against such a blop, instead most things will suck against it. Archers will only have to shoot the shields in the front and cavalry which needs to attack from the sides or the back to catch unaware targets would run into pikes. The only thing that has equal chances against such an infantry formation is another infantry formation.
So buffing infantry for the same classes playing together would motivate the wrong behaviour.
