I just want to make sure I read everything right and get the input of others to be sure. If you've not done 10 preseason games prior to the patch tonight, you'll just be placed into a league based on your performance during your first 10 games under the new system? In other words, if I've done 0 ranked games this preseason, doing a few tonight wouldn't impact me going into these changes? (unless I somehow hit 10 games in 1 night)
The ranked matches that you have played will have an affect. If you have completely avoided ranked, then when you start up after the changes it will place you then. If you are already ranked, they have a magic riot equation that gives you your league and division based off current elo compared to your top elo relative to all players on the server. --- welcome to the world of online gaming, where nobody is your friend, and your friends, yeah they hate you too.