I looked at old Polynesian units sets and it contains 15 units (archer, axeman, chario, crossbowman, cuirassier, explorer, h.cav., heavy footman, horseman, longbowman, musketman, pikeman, rifleman, spearman, swordsman).
Entire ethnic set include ~170 units.
15 units its less then 10% of all needed models and I think its not a big deal to add then back. But most of the units still will be the same (not to mention all non-human units - ships, tanks, vehicles etc which are mostly the same for all ethnic styles). Only one question - which style is correct for them? SO propose Australian (mostly European units) for Maori and Asian for Polynesian. My proposition is to use South American style mixed with Asian and European if needed.
We're supposed to have one artstyle for each fundamental continental culture and it should apply to all the civs of that culture - all more specific artstyles can be entirely optional imo.
There is only few models for Oceanic civs and as I mention before we need around 170. Ofcourse I can retexture models from other civs or use 2 or more times same model from Polynesian set. But in the end this look weird and cheap.
Looking from my perspective and experience of adding set of units I have one advice guys:
1. I can add these 15 polynesian units and rest of the units taken from South American set
2. Include in C2C one full set from more popular civs such like Rome, Babylon, Japan or Mongolia. We have plenty beautiful models for these civs and in the end our players choose Rome before Polynesia in most of the plays.
Ah one more thing: new set = ~27 Mbs and ~900 files.