It's funny you're complaining about cav after you changed to infantry. You didn't find cav annoying before, did you?
I don't see any reason to make horses even more expensive. If raising the upkeep is an idea, raise upkeep for every item!
I have cav alt and i will put points in riding in my main. It was annoying even before because when Gk joins one team would get 20 cav,and other team would be just pray for horde of mongols.
I would ride a horse if i want no matter of what,but low gens and noobs couldn't ride a horse.So that is the point.
Every bigginer that get killed few times,rages and go straight to cav,because it can get cheap kills.
This would actualy lead to cav becoming a pro class and not being hated so many.
Don't careyou can tripple it if you want i would still make money and use my mw stuff no matter the cost.
Only nobles and knights rided a horse,and had good armors,not every peasant was able to be cav.