The Aliens were not weaklings either, at least in the first movie anyway, that said, Grid never actually won a fight, it killed one predator by being stealthy, completely in line with their nature by the way and it killed Celtic because of the latter's idiotic behavior. Celtic won the fight but lost the night.
Predators were not super brutes either, Celtic and Scar were incompetent, the former more so. Though I didn't like their design, masks were fine but their physique and faces were not.
Now if you was talking about AVP-R then yes, the Xenos were cannon fodder and Wolf was a walking tank.
The pyramid concept is not a bad one at all, don't get the hate about that.