@Riot, here's a simple solution that would satisfy the core of a sandbox mode.

Over the years there has been loads of discussion regarding the possibility of implementing a sandbox mode where people can practice various skills, but exactly how this would be implemented doesn't appear terribly often. Maybe this has been suggested before, but I'd like to raise the discussion (possibly once more) regarding a simple addition to single-player custom bots games.

It all boils down to cooldowns. Farming to level 6 doesn't take long. I don't even think acquiring items is the gating factor. It's all about waiting for spells to come back. What if, in single player custom bot games only, we added the option for a hotkey that reduced your champion's cooldowns (abilities and items) to 1 second?

I see several benefits to this.

1. Practice those flash combos all day!
2. Much easier to implement; no fuss about stationary minions/champs, just add it to the infrastructure already available in single-player custom bots.
3. It doesn't allow for urf-like gameplay training. Cooldowns remain the same as always for more realistic training, but once you finish, you have the option to hit the button and reset the cooldowns. Same goes for mana-gating. It allows you to practice with a realistic mana pool based on your items. This is no issue since you can just recall when you go OOM.

Let me know what you all think. I'm personally not concerned at all with time spent leveling to 6 or earning gold for items. I mostly care about ability/item combos. I feel as if this is would be a simple solution and would satisfy most people in their quest for a "sandbox" mode.