Applying a VP bonus/penalty is of course a possibilty.
We already had some attempts like this here (without names):
There we've also discussed the use of the use of average VP to determine a faction's strength:
It is commonly agreed that this is not the best value to measure the strength of a faction. This is because factions also influence the scores of their opponents more or less.
An example: Cultists usually get a lot of points from cults. While their average score is only... average, they are still one of the strongest factions. They simply take away possible points from other factions (who will get less points from cults) and therefore they need to score less points to win than e.g. their brown brothers halflings, who score extra points by digging (which does not hurt anyone).
Halflings are considered one of the weaker factions, still they are among the top of your average point ranking, while usually stronger Cultists are in the middle.
I'd suggest that you look at either average position or average margin (score difference) instead.
So maybe you want to adjust the values in your list to fit average margin instead.