Idea called "The Training Grounds"

Can there be a map or mode where you just practice skills freely ? No cool downs, option to level up faster, and don't lose hp. It can be a small map a circular one would be cool, you and other 4 players are just fighting minions/bots practicing your skill shots. For example, someone who wants to train the Alistar combo or any combo can go into the Training Grounds. And maybe implement a system where you're free to leave and other people can join. What do you guys think? Could even be good to train combos with your teammates for serious teams.