That's perfectly fair. What amendment to his bio would you like to propose?
I do think the acidic secretion whenever emotionally provoked by the overwhelming sense of fear he senses from those near him is a factor, though it admittedly doesn't explain Man-Thing's ability to burn intangible entities.
Acid is listed on his
Marvel wiki entry, same goes for the
Man-Thing wikipedia page, and several other resources, as well.
But to what extent does this make up his burning touch? Perhaps the secretion is somehow interdimensionally permeable, which would, despite being highly speculative, make
some sense, considering Man-Thing is also interdimensional?
As for his intelligence level, just about every incarnation of Man-Thing gives him a slightly different sense of his surroundings and past. I'd say somewhere deep down he has his memories and intellect, but I didn't add that part to the bio. He's even been shown speaking, etc., so I do think something should note that in the powers section.
Does this change suffice, or would you take it further? (I've bolded the added detail).
Thanks for bringing this up by the way, as it only helps all of us to better grasp and understand this fascinating character in even more detail!