Sandbox mode
"We’ve heard a number of player requests for a Sandbox Mode, with two main reasons: the first is trying out new content – which is something we value too. We want players to know what they’re getting and to be happy with the things they’re unlocking (we may investigate other ways to do this). The second is that players want to practice very specific skills without the constraints of a regular game. For this point, our stance is that sandbox mode is not the way to go. We want to make sure we’re clear: playing games of League of Legends should be the unequivocal best way for a player to improve. While there are very real skills one can develop in a hyperbolic time chamber, we never want that to be an expectation added onto an already high barrier to entry. On an individual level, we know this isn’t always true – some just want a space to practice flashing over walls without having to wait at least 3.6 minutes in between – but when that benefit is weighed against the risk of Sandbox mode ‘grinding’ becoming an expectation, we just can’t accept the tradeoff. We never want to see a day when a player wants to improve at League and their first obligation is to hop into a Sandbox. We do want to support your ability to grow in mastery, and there may be other avenues to do so, but not this."
Just another reminder that riot does not want sandbox mode because people would get better too fast. In other words it would be effective and work as intended.
Reasoning? The learning curve would be steeper and so less casuals will want to play and there may be some sort of profit loss ad a result.
Never claim to be a sport or esport again then. In any sport, people will practice a specific skill they need to improve on if they are serious about getting better.