That’s the issue though, a tier list doesn’t really clearly show if a hero is weak or strong - it’s entirely subjective and varies depending on the person creating the list.
A hero listed as C-tier by one person might be considered to be “average” while someone else might consider that same tier to be below-average. Simply stating an average tier-level for a particular hero (like the person I originally replied to) adds an extra layer of abstraction and obscures the actual opinions of the original list-makers even further. It implies a level of consensus that simply isn’t there, because C-tier has no universal meaning.