Jaguars, horse archers, immortals, ballista, mohawk warriors etc all put maori to shame in terms of usefulness. Just compare maori Vs jaguar. Jaguar would simply crush a force of maoris. Jags are better for barb hunting, exploring & heal after kill is insane if u know how to use it. Fear promo alone doesn't do much.I think who vote the maori down, does not really play with it.
Basically what it does, it creates a warrior, that is 11% stonger than a normal warrior. And it carries over. And it affect the arches behind him. It it is available from the beginning of the game to the end.
It is one of the strongest unit in the game (in SP, where you can be carefull not to kill them)