It's cool to see the research and thematic detail in the mod! I like the Dreamtime theme. Anything you can put in to expand on this seems like it'd be a step in the right direction. On to the nuts and bolts of things, though.
Firstly, call Mimis seems bugged. I got some unnamed legionnaires appearing on the edge of the battlefield. The Dreamtime warriors seem pretty pricey for their benefits. As far as I can tell, the Rainbow Serpent is just a traveling astral tempest. The description seems to indicate it might have another impact .. is that the case? Maohi Javilineers are awe-inspiringly good for the cost. 2 gems and a mage turn for an unarmored immortal with dubious surviability is hard to carry if it also causes unrest (Maero). The recruitable mage variety is really nice and everything feels like it has a niche. The Wakataua masters don't seem to have a function, though. 10 leadership isn't enough to make an impact. Increasing the leadership, giving them stealth and/or priestly powers would introduce a role, and the semi-religious nature of sailing would support it.
While the above is pretty negative, I'm mostly focusing on things that, as a player, I would like changed. There's a lot of the mod that doesn't need changing one bit, so I figured I'd just put all of that into one big AWESOME! at the end.
AWESOME!