Shop interface (a must do suggestion)
A I am very dissatisfied with the huge role of random and pure luck in TFT now, but even if the devs love...no, ADORE their perfect and precisely balanced random mechanics, one thing should be done for surem just to make the game more user-friendly.
There is enough space both in right-click champion menu and in the champion card in the shop, to display how many copies of this champion are left in the shop. It will help to manage rerolls without studying bench of each player between rounds. Particularly, it will provide the chances of getting 3-stars.
If riot don't change this rng system or at least make it more comfortable, they risk to lose players, and as I see on this forum, it has already started.