Here's what I've taken from the suggestions that I like + my own ideas.
I updated the initial post to add this list as well.
a. Inf get free light torso armor (better than the free stuff they are offered now) and cheaper medium and heavy torso armor: An advantage infantry should have is armor, but while heavy armor is this unaffordable , it's not much of an advantage. Also, inf light and medium torso armor isn't much better than what cav or archers/xbows get, so inf should at least get a better free light torso armor and cheaper medium torso armor.
b. Cav torso armor cost remains the same: Because cavalry don't have to deal with the weight penalty thanks to their horses, their armor costs are currently well balanced.
c. Archer/xbow torso armor cost remains the same or decreases slightly: Archers and xbows can effectively double as inf when they grab shields. If inf armor changes from 'A' were implemented, then archers and xbows wouldn't be as effective at this hybrid thing anymore, which is good because inf uniqueness needs to be preserved/established.
d. Helmet costs should be slightly cheaper across the board and certain faction units should get a better variety of helmets: Overall helmet costs seem a bit high right now (for example, the Rhodok inf's best helmet costs nearly 1k) when compared to the benefits a helmet provides. Headshots are relatively rare, which means most of the time a helmet is simply a weight penalty. Also, some units need a better helmet variety, such as the nord inf, who needs some cheaper helmets.
e. Make leg armor costs way cheaper across the board - Very few people buy leg armor due to how expensive it is. Its price should be universally reduced to make it more cost-effective.