Given we know essentially nothing about Eson, this is a rather dubious fight. IMO, direct contests should be restricted to characters where we have a reasonable amount of data to judge how powerful they are.
Keep in mind once the characters have found their placements through battles using the information available, they will continuously be updated as new on screen battles occur. For example perhaps back when Thor and Hulk fought in the first Avengers movie perhaps someone walked away with the feeling Hulk was able to take down Thor, making Hulk seem very powerful indeed, but then in Avengers Age of Ultron they saw him get punched out by the Iron Man Hulk Buster armor, (sure maybe he was calming down already, but whatever everyone sees it differently). Then there is the battle between Thor and Hulk in Ragnarok, which could showcase him to seem more powerful or not as very few people have been able to see it yet. My point is that if a Thor Vs. Hulk battle was done back when the first Avengers Movie was made they might have appeared on the list like this.
Hulk
Thor
However, after seeing Age of Ultron perhaps people would have viewed Hulk's placement against Thor like this
Thor
Hulk
Then again after seeing Ragnarok perhaps the crowd will view their placement like this
Thor / Hulk
By the way it is possible for them to be at the same exact power level if in the Vs. battle they both end with an equal number of points. However, my point is only that peoples perceptions will be ever changing as new material becomes available, so we will as new movies come out revisit characters to see if anything has changed. So, we should be voting based on what information is available and yes on some characters there may not be a lot to go off of, but when that new information becomes available we can always re-categorize them based off the new information. So, right now it looks like
Dormammu
Eson
But in the future he might reappear and it's possible something might establish him to be way more powerful then previously interpreted and then a battle between Eson and Dormammu could occur again and it could end with results of......
Eson
Dormammu
based on the newest information.
So, it will always be a work in progress and changing with new information. Hope that helps.
Surfer