I clearly have a tournament scene in my area, and I enjoy practicing with people locally who are good at fighting games. I have even more incentive to stop playing online, lest I learn bad habits and techniques to handle the fight.
Online will never be consistent, no matter the game. You are always, always better off learning from other people in a controlled environment, i.e. a console or arcade. An environment that won’t change or get worse or better depending on lag. Get some friends, and play with them if you don’t have an arcade nearby. If a game is as good as Kof12, it shouldn’t be an issue to wrangle people you can play with consistently.
Online is not a deal breaker for me because of this, and it shouldn’t be for anyone who has any degree of social skills.
Also, I’m hesitant to randomly throw out percentages that haven’t been confirmed or even researched, because that’s just dumb. “90% of people play games online, 70% of people hate kof, etc” are all uneducated made up numbers based on assumption and in no way reflect the reality of the situation. You need to go out and find people to play with and convince them it’s a good game. If you don’t do it, then don’t waste your time complaining.