How do you justify the xenomorphs as boring?!
If anything, the predators are the more boring of the two because they are not hardened enough creatures to be able to fight the aliens without having weapons.
The aliens have a completely diverse and complex bio mechanical body structure, plus their life cycle is amazingly abstract and unlike anything ever shown before.
The predators are basically like humans but with crab like faces, they are a relatively civilised race with technology and small communities, that makes them less original and in effect - 'more boring'
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