I think we were gonna get other areas sooner and therefore get to sahagin sooner, but since the game was release as early and blemished as it was, that all got put on backburner.

The sahagin give people power, and in turn those people become reavers and fight our own kind, so not too friendly

Sahagin- leviathan
Kobold- titan?
Amaljaa- Ifrit
Ixali- Garuda
Gigas have been mentioned by someone saying npc dialogue brought it up, they'd prob have shiva if in game.
That leaves Ramuh for sylph maybe?