A better way to practice League of Legends

As much as I know this idea has been thrown out there, I think that a sort of sandbox mode would be awesome. Just imagine, instead of starting a game and only getting to choose the map, what if you could choose how much CDR you started with, or how much gold you started with. The possibilities are endless, and this would tons of fun for you and your friends. Also you could use it to practice. For example, if you could set the amount of CDR or place bots with specific movement patterns, you could practice insec kicks on lee sin, or you could practice combos on zed. Those are just mere suggestions but I personally think that it would be a great addition to the game.