Most people picked Taltos because quite frankly, they seem to have the best bonuses.
They only have a penalty in deer hunting and considering it doesn't say "food gathering" I bet there's a secondary way to get food (farms, gathering).
On the otherside their best units cost 25% less resources, the "trickling?" rate of resources is way higher, good defendably territory with chokepoints, etc. etc.
I realise that this is merely a preview and there's no way we could know what the eventual bonuses would be but based on this information I'm pretty sure Taltos is going to be overpopulated compared to the other regions.
I've given this matter a bit of though about how to handle this at launch. There's 2 ways reverie could handle the matter of territory picking at launch.
1: open, like they showed us here in this FF. Before you pick you get to see exactly what the bonuses and penalties are in that particular are.
2: general, instead of saying Taltor had 25% cheaper military, 25% cheapers alchemists and 25% decreased deer hunting they'd say "Taltor is a border land, troops are easy to come by. The elves of Taltor have mastered the art of Alcemy. Due to the industrious nature of the inhabitants of Taltor deer populations have dwindled." or offcourse woven into a nice little story.
Personally I'm in doubt between the two, the power-gamer in me would vote for 1, anything to get an advantage over other players. Also more players means less space means more war. The concerned gamer would vote for 2 because it would spread the population more evenly among the regions and probably less balance issues.