Better to ask if they gonna do something with the champs that appears only in 1-2 copies. Like when my shop was flooded by yordles and I made my comp around them, I had only 1 Gnar. One little 1-star Gnar at levels 7-8. And never have I seen it in the shop anymore, neither my opponents had him, except one guy that also had only one 1-star Gnar.
And some time ago, in previous patches I played a game where I had only 1 graves that I got from roulette at level 1. Never more I saw him in the shop neither in the following roulettes.
That's kinda awkward if it's the character you need.
Especially this works for aristocrats. Once I had 3 DAYS gaming without seeing Kayle anywhere in the game. 2 Times I lost the opportunity to win the game, cause I haven't made it to the 6-char buff, and finished 2-4 places instead of 1.