saying it takes play time is obfuscating part of the problem, other games can take play time to unlock stuff, but while you're unlocking that one thing, you're also unlocking other things aswell concurrently, and by the time the biggest thing is unlocked, most of the other stuff will be unlocked
but thats not how it works in BFII,
while you're spending tens of hours unlocking Vader, YOU ARENT ACHIEVING ANY PROGRESS TOWARD ANY OTHER UNLOCKS OR PROGRESSION, you are focusing 100% of your time and savings just to unlock that one champion, and then when hes done, YOU HAVE TO DO THE EXACT SAME THING FOR EVERY OTHER CHAMPION YOU WANT TO PLAY WITH
if you want to buy loot boxes and upgrade your arsenal WHILE you're saving up for vader, it will take you probably twice as long to get him, you cant just saying "i have to play the game for 30 hours to get vader", its more like "i have to play for 30 hours AND give up 30 hours worth of arsenal upgrades in order to play as vader"
unlocks in Battlefield II are CONSECUTIVE, NOT CONCURRENT