"Isn't life, by nature, a contest decided by a single round? However trifling the matter, it's not possible to return to the last save point by pushing some reset button." - Kazuki Hoshino, Hakomari, Vol. 1
Seriously, this was a no-brainer. The Oreimo was pulling in about 25K average per volume. You'd have to be an idiot to not to want to do a second season of it. Especially with the drama between the characters really heating up.