As a warlock, which covenant would you pick if their performance and utility was equal, i.e. their only difference was in theme and cosmetics?
For comparison, this is how the warlocks have actually chosen their covenant as of now (from wowhead):
1. Night Fae (40.5%)
2. Kyrian (30.1%)
3. Necrolord (17.5%)
4. Venthyr (11.9%)
We can compare these data with the results of the poll, and see how well Blizzard succeeded in "allowing" the warlock playerbase to choose the covenant they want (i.e. the one that thematically fits the best).