Riot, the reason I want a sandbox mode is not to practice mechanics but to experiment.

I enjoy experimenting on various builds , ( trforce + multiple steraks, full AD on Jhin for insane crits and full atk speed on Jhin for insane m speed bursts etc etc ) champion kit interactions ( Vel'koz W vs Yasuo windwall, Tahm Kench devoured minion with Zil bomb on it etc etc) I also enjoy a lot numerical tests and data:

• full armor pen Shaco Q crit does 1782 dmg vs a 60 armor target -full crit damage Shaco Q crit does 1657 dmg vs 60 armor target

and stuff like that.

Please let me and fellow gaming scientists express themselves. Don't even call it sandbox mode, call it League's Lab .