It's true that there isn't a way to increase the effectiveness of "cannibalize", while Otyugh can grow itself, can get boosts and can eat previously damaged creatures. So less points for the "eating"
But don't forget that the grow ability is really bigger compared to Otyugh. So more points for "growing".
I think that Cannibalize can be considered equal to Devour.
Also, don't forget to count regeneration!
Its based on your theory:
The percentage of creatures that can be cannibalized is a little less than 10%. = 1 quanta. > Correct.
Count also the growth effect, that is bigger than Otyugh growth effect. = 1 quanta. > This is what I think its incorrect, because it gains more attack but dont increase skill efficiency (skill is surely more situational).
Troll regeneration: cannot be targeted, it's free. = 2 quanta. > Correct.
The ability uses another element. = -1 quanta. > Correct.
The total skill value is 2 quanta.
Attack = 4 + Skill = 2 - Element Bonus = 1; Total = 5.
Of course, would like to test, but for now dont see it as OP.
it fits more 
than 
, and considering how low cost 
creatures are, it shouldnt be difficult to keep this thing fed when a cheap creature with mitosis, or two, is around
I think it fits
and
as well. I thought it would be more interesting in
. Surely keep feeding the troll is possible and intended (lol, thats a strange sentence in forum context), although its a vulnerable combo and, I believe, slower than mono life rush. Of course, it could use the protection of some
cards, like Cloak and Dusk shield to be more effective.
