I've played this game since the beginning of season 3. I love it. I've spent more money on it that I am prepared to admit, and as daft as it may sound, League has helped me work through a few very difficult points in my life.
Since I started playing, before Team Builder was a thing, all I wanted was to not have to argue about what lane I was in, or what champ I wanted to play. The whole "whoever shouts mid first gets mid" system was ludicrous. Team Builder completely changed this for me. The "lengthy queue times" mentioned by RIOT in there "replacing Team Builder queue" where never what I would call "lengthy", and where a tiny price to pay (in my opinion), to be able to play exactly the champ you wanted, in exactly the role/lane you wanted to play them. In the years that Team Builder has been available, my enjoyment of the game has only increased. Sure, arguments in the game persist, but "mid or feed" was gone.
Now I read RIOT are scraping team builder. Ok, so its not being thrown out completely, but being "guaranteed to get one of the two positions you prefer" isn't what I'm looking for. This is the champ I want to play, and this is the role I want to play them in, done. Team Builder is a normal game mode, its a bit of fun. Why should it be dictated by other players what it is I want to play?.
In my opinion, the new champ select will only provoke more fighting. RIOT's perception of this (famously) poor community baffles me a little. "Teams get on the same page and start working together". Sure, this may happen in the higher Elo's, but down where the VAST majority of the player base is, all I can imagine is people arguing about champ "X" being weak.
TL;DR: I'm frightened of change, and I'm going to really miss Team Builder.