Best of the best, pick or ban them early. Popularity > 40%.
The above average heroes which fit in most situations. Popularity between 40% and 20%.
These heroes are average and can fulfill your draft .Popularity between 20% and 10%.
Niche picks, heroes that only have a few good maps or are just subpar. Popularity between 10% and 4%
If you want your to troll your team grab one of those heroes. < 4% popularity.