I think Traits are something that should be dumped or transformed into something that changes over time with player decisions. They should be earned, say by building Great Wonders or qualifying in some really difficult way, not just picked before the game starts. Like Spiritual could be earned if you maintained a state religion for X amount of time and built X amount of religioius buildings. Could this potentially imbalance things in favor of those who are already winning? Not that much, because to earn a trait you would have to make sacrifices. While building all those temples you aren't building the markets and towns and roads and harbors needed for Financial. You are maintaining a state religion that may cost you diplomatically. It isn't, "Hey, I"m the most powerful civ so I can get all the traits!"