I feel your pain on this one, it's been something that has happened to me as well. It makes you wonder if when you report someone for something said in chat, "does Riot get the FULL chat log, or just the in-game chat?" Not to mention the flat out hate you can get for picking a specific champion to go to a lane they CAN do but people want you to pick a specific champ for a set meta. It is getting to the point right now that if you try and do anything off meta you get instantly hated on, flamed, and quite often you get guys who become toxic enough to feed.
This often happens to me when I pull Teemo out, yes EVERYONE in this game HATES Teemo. I have become pretty good with him however. BUT if my Jungle decides he doesn't like that I didn't pick a "Tank" champion then he decides not to ever come help me or gank my lane then I end up being bullied and often the enemy JG picks up on this and starts camping me for free easy kills. No matter how good you are with a champ when you get hit by a laner and JG pair you often either just barely make it out or you get killed, unless the JG is just bad at ganking or you had enough wards up that you spotted it early. Then there's the tower diving, if you have to face a JG like Yi then you have a player who can turret dive with the other guy and they trade the Turret dmg cause of Yi's Q and you can't really get either unless you are just good enough to do so or are ahead on farm and have the items to do more dmg and self healing. When this type of situation happens and you see your JG just sitting at Krogs, (or whatever you call those 2 rock guys that become smaller versions of themselves), and literally types in that he refuses to help, all cause you didn't pick what he wanted you to pick, then this is your JG feeding you to the enemy team.
I also agree that dodging doesn't have enough of a penalty to keep people from doing it, not to mention it messes up people's champion select when you are most of the way through it and someone leaves. Then instantly you get matched again but 3 of the ones who were on your team and saw your declare and/or pick now lock that in as a ban. It doesn't break the game, no, but it does make it annoying. Not to mention the point where you are in a good setup for the team and suddenly someone AFKs or dodges and instantly put back in and now you been auto filled to support. This generally annoys me, I don't really mind support cause I can handle it ok, but it is the fact that had the guy not dodged I'd not have to worry about this at least till next game. But anyway, I do think if someone dodges then the match making system should put you with completely new players, not someone who just saw your declare and knows to ban this champ, this champ, and this champ cause someone picked them before the dodger left the game.