rotating game mode idea based on ultimate bravery

I know there has been many requests for something like Ultimate Bravery in the rotating game mode system but I think the main reason Riot is against it is that a lot of it would just come down to the randomness of the build you get. Similar to how ARAM can sometimes boil down to champ select but even more frustrating because you have less control.

My idea is for a game mode where the items are assigned at champ select, like ultimate bravery, except first you pick an item set, then pick a champion to build that item set on. For example, when you load in to champ select each team is presented with the same 5 randomly generated item/summoner spell sets (same 5 sets for each team for fairness), and everyone clicks on one they want (first click gets it might be the easiest way to do this, but then allowed to trade after they have all been assigned, if someone doesn't pick they get randomly assigned what is left). After 10 seconds of picking an item set there is a blind pick champ select followed by time to make runes and masteries (I know masteries are usually assigned in ultimate bravery but I'm not sure there is a realistic way to display those easily when you are deciding which set you want).

I feel like this could lead to some neat ways to think about champs and some different team comps and play styles (what if all the item sets had smite? etc.)

example champ select:

any feedback on this idea is welcomed :D