Agreed. Poison damage remained the same after 10 intellect was added. (60 matk I believe?).
like i said i tested it in the 1 hour i had in open beta last night, int which coralates to matk did not increase Tick damage on the aoes, just the initial hit from it. and aoes almost never crit, maybe 1% if that ive seen. So overall the only thing that really amps up the aoe damage is weapon and level
just made some small tests. main reason was to check which buff is more effective
[bruiser buff or defender buff]
Armor (with self buffs [death mantle lvl1 and golem aspect lvl3] ): 711
with defender buff: 811
Tests was made on Gremlin Berserkers.
poison arrow 3lvl = ~100 dmg + 38 dmg per tick
with bruiser buff (356 MagAtck) = ~107dmg + 41 dmg per tick
Night terrors 1 lvl = 144 dmg + 37 dmg per tick
with bruiser buff (356 MagAtck) = ~153dmg + 40 dmg per tick
[it seems MagAtck effects dmg but veeery small amounts of it]
without defender buff  got damage:
with defender buff  got damage:
so still don't have clear picture but feels like what deff buff better. [less heal, dmg aprox, same]
of course need to try with more int, to check how it impacts dmg.