Tier 1
Strong in the meta, they're usually picked after "God picks"
Tier 2
Strong in the meta but on more specific draft and lack of something (Global, Waveclear, CC, engage [...])
Sometimes used to counter opponnents heroes
Often picked in the second rotation
Tier 3
Heroes that must be in a specific draft to be powerful, you pick them WITH or AGAINST certain heroes
OR
You are very confident on it and think you can carry with it on Storm League
"Niche" picks