Any elf in Thedas who wants to provide the blueprint for Thedasian government should use terms Thedasians might know. No appeals to concepts or anachronisms that have no meaning to them: if you wish to describe it, use terms they will understand.
Any elves who want to build a nation in Thedas will be doing so without words like 'Swiss', 'confederation,' 'federal,' 'parliamentary,' 'republic,' 'governmental accountability,' 'elections,' 'fair trade,' 'eminent domain,' and even 'nation-state.'
Very true. Of course, there will be always a first government in any society that couldn't been born from previous governments, because they didn't exist, and governments that were shaped by necessity and external conditions, but western liberalism is the product of centuries of political discussion before it could be put into practice. And it has been changing ever since.
So what are the current models Thedas can offer?
Feudal system is the norm in many places, with a king/emperor on top and vassals below, who have other vassals and so on. There are also some form of parliamentary politics in Orzammar and Tevinter (it's no coincidence that Tevinter copied a lot of things from the dwarves), limited by class (nobles in Orzammar, mages in Tevinter). The Dwarven city of Kal-Sharok seems to have a more advanced parliamentary system, but we know very little about them. Unofficial plutocratic oligarchy is in effect in Antiva. As for the Qun, their system is a strange form of totalitarian meritocratic collectivism.
The elves will probably look first to their own systems. What do we find there?
Thanks to Arlathan, we can guess that the old elven kingdom was a classist society with mages on top. Orlais seems to be the preferred example to describe them. We know little about the Dales, so it's difficult to say, apart from their isolationist policies. As for current elven societies, the Alienage elves offer the figure of the hahren, a bit of a mediator and spokesperson. Interestingly, despite having also the title of "elder" the position is not given to the oldest member of the Alienage, but to the one who is the "wisest, cleverest and most level-headed". That's a good start. As for the Dalish, we know that they have two sources of political power: the Keeper, the senior mage of the clan, and the elders (if they are "elder" in the same way as the City Elves' elders is something we don't know). The way power is shared seems to be different depending on the clan. In the Sabrae Clan Marethari's word prevailed, even if many in the clan wanted to move, while in the Virnehn clan important decisions had to be made by the elders, not just the Keeper. TME also introduced the figure of the "warleader".