(Copied my post from the regular forums because this is a better place to leave feedback for pbe stuff.) :P
I was talking to my teammates about it in champ select, and they said to highlight a champion you are NOT going to pick, because if you pick a champion for a teammate to trade, they will have an idea of what your team looks like before it is chosen.
The problem is when it is your turn to choose a champion, it will automatically select it and reveal it to both your team and the opponent before you've locked it in. An example is I had Brand highlighted for my pick as second pick. Our first pick was our mid laner, so immediately when it became my turn to pick, it revealed Brand. I chose Lucian for my ADC, who was last pick. Now the enemy has an idea of both before one was even picked.
It really does take the surprise out of the champion select if you plan to exchange champions before the game starts. I think you can already predict seeing a lot of false 'preferred champions' in tournament play simply because of this aspect that shouldn't be.
Just some food for thought before you release it out. Maybe it can be patched, maybe it will go ignored. Heck, you don't even have to select a preferred champion. Maybe that step will be completely skipped by the masses.