These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Evil Is Sexy: Say what you will about Maia, but unlike her brother, the Dark Eco didn't seem to do anything negative to her body...
Fridge Brilliance: White light is the origin of all other colors, and black is the absence or complete absorption of light, so it seems reasonable that combining the four non-Dark types of Eco would create the Light version.
Fridge Horror: The Lurkers may not really be evil, but just slaves.
Wangst: The warrior in Rock Village. Daxter even snarks about it:
Daxter: Have you tried attacking him with your melodrama? Cos it's killing me!