CoC Haki Skill Tree:
- Lv1: Basic CoC without any control (example: Impel down Luffy)
- Lv2: Basis CoC with control (example: Post Time-Skip Luffy)
- Lv3: Advance CoC, imbuing attacks (example: God Valley Roger)
- Lv4: Advance CoC, imbuing defences (example: God Valley Rocks)
- Lv5 (MAX): Super ultra strong CoC that trumps any bullshit devil fruit (example: Joy Boy's knot)
Roger and Shanks on their Prime both reach Lv5 on their CoC Haki Skill Tree and that's what put them on another Level to the rest.
This is what Oda just send me, so you can all stop your powerleveling debate.