I think the biggest deciding factor for me on nation is “Is this where my mates are?” Do I want to be a part of the group that I’m spending most of my time with or do I want to be the odd-one-out? If I’m spending most of my time in the Brass Coast anyway, I want to be Freeborn. If I’m all about the Songs and Story Time Life, then I want to be Navarri. If I’m stalking the Rusty Compass, then I would want to be Varushkan.
Given my play style(goal-oriented achiever/explorer), I look at building a character like buying a tool kit. Figure out what you want to do in game and select the tools that make the most sense for the job. Most goals can be reached from any nation, but many goals are more easily achievable from certain nations, depending on the resources and attitudes in those nations. So, my follow up question to where my mates are at is, “Can I approach the part of the game I’m interested in, from a mechanically viable start position if I stick with my mates?”
For example, if I want to get involved in a broadly political game and want to maximize my individual voting power, I may want to play an Urizeni priest, since it’s the smallest national assembly. So I take a congregation and I might want to dedicate myself to the virtue assembly with the smallest numbers, say Ambition. I might want to play a mage with lots of ritual lore to increase my votes for my territory’s senator, probably the territory with the smallest numbers or another advantage, say Redoubt. As a mage, I can start as a member of an order, let’s go with the smallest or one fitting the political mage viewpoint, the Celestial Arch. As a ritualist, I pick up Mantle of the Golden Orator to enhance my congregation, and since it’s an Autumn ritual, I can find/create an Autumn coven or pick up another Autumn ritual, Aid Once More, to increase my uses of Volhov’s Robe per event and temporarily join other covens. Now I’ve got my fingers in the Senate pie, Conclave pie, Synod pie, and Ritual-pie. I don’t have a mana site, so I’ve got a thing I need(mana). I will pick up knowledge of events going on and some political influence as I play. I’ll also have ritual ability to offer.
While I’ve got a bangin’ character idea (Urizeni Autumn Mage/Ambition Priest from Redoubt who is a member of the Celestial Arch), if all my mates are playing a group of Wintermark Monster-Hunters, I would question “how often will I be able to interact with them and what kind of relationship will we be able to have?” If you can have a chat with your mates and work out answers to those questions that you’re satisfied with, you’ve got your choice. If not, then you can modify your concept to fit the group a bit better(maybe to a Suaq Autumn Mage/Ambition Priest who is a member of the Celestial Arch for example) or maybe choose a different goal.
In any case, there are tons of people that have 5+ back up characters in the system, just waiting for their current character to die.