As long as I've been here, battle quests have always been like...challenge an opponent, get some exp and buy stats...I don't know if they ever just gave stats directly though? 0.o
I'd swear there were quests where the quest-giver would tell you to take on a certain opponent and then when/if you beat that opponent, you could go back to the quest-giver and they'd give you a prize, which sometimes included stats. What you're talking about is just the regular battle coliseum.
No there is still quests like that http://subeta.net/games/battle/quest.php he gives exp and a prize and you buy your own stats...