Possible new game mode

Every time I buy a new champion or just start playing them I often wish that I could just try different builds on them just to see how it would go. My suggestion is that Riot makes a new custom game mode or a coop vs ai where you start off with enough gold to buy any 6 items you want. Everyone would start out level 18 too, to make it more realistic. This way, we can try out any builds we want and it would just be practice. You wouldn't have to wait until 40 or 50 minutes to get a full build. I believe this would both be a lot of fun to try out new builds and helpful when you actually want to play a real game, having came in with a new and improved build. I also believe that this would introduce more creativity into the game, so everyone doesn't use the same exact ahri build, or the same exact Lee sin build. I really hope that you would follow through on this idea and maybe even keep it for a longer time than other game modes. Thanks for taking time out of your day to read my idea on a new game mode for everyone to play!