Mastery Ideas
When I select Inspiration as my main path, I want to really take advantage of thinking outside the box by warping the general rules. I have a few ideas for cool inspiration masteries that will help achieve just that. Mind you, I am just throwing ideas out.
The following mastery would be another keystone mastery. It would focus on team composition. At level 13, you would be able to gain a team member's passive ability in addition to the one you have. This does not take it away from your ally. You keep this for the rest of the game.
Say you're 
and you have a 
support. Take his passive and spam those abilities.
This next mastery would greatly increase your sight range.
Another mastery I would love to see would grant sight of the area you died until you respawn, like a ward.
Another fun one would be to give allies your gold.
I want to see Hextech Flash turned into Hextech Spell. It would apply to all summoner spells, allowing you to cast a weakened form while it's on cooldown.
Have you ever been not able to dodge something because a wall was to your side? What if there was a mastery that allowed you to walk partially in a wall. It would not allow you to go all the way through- more like the wall is thinner.
The following mastery would start you at a higher champion level.
These next masteries are random ideas for the other paths.
Domination mastery that increases the duration of your stealth.
Resolve mastery that increases the duration of your crowd control.
Resolve mastery that blocks the next turret hit (has a cooldown).
Sorcery mastery that allows you to reach higher levels. Upon obtaining these higher levels, you can upgrade an ability to lower its cooldown or resource cost by a percent.
Precision mastery that allows you to get a third tier on boots. This third tier would increase attack range.