I bet that people having talents isn't going to be as rare as they've been making out. Now having the necessary knowledge, experiences, skills, and encounters necessary to recognize you have a talent, realising what the talent is, let alone actually unlocking it and putting it to use, now that I bet will be extremely rare.
For example: You have this brand shiny new character and you decide to make him a blacksmith, not knowing he has a talent. You spend the characters life making him a grandmaster blacksmith, making him one of the most famous blacksmiths in the kingdom if not all of Elyria. This gets you elevated from just a regular commoner all the way to say baron or count. Now as you no longer need to work all day in your smithy (unless you want to) as you have enough money and rank to suit your needs, you decide to start learning another profession in your waning years, cartography. It's when you advance your skillsets in cartography enough to become a journeyman cartography you discover to your surprise that you have a talent, an unknown talent. It's as you become an elder in life you finally atain the rank of master as a cartographer only to discover the conditions for unlocking your talent, you must become a grandmaster cartographer, and create an absolutely perfectly detailed map of the kingdom that you are a part of. To make a long story short, you wind up on your deathbed as a grandmaster cartographer, but as you are making one last attempt to create that perfect map, your character's life.......ends. I bet we will see more than a few stories about talents where characters died before they could unlock them. Whether or not my predictions about the number of talents and the requirements to discover them will be true or not well we won't find that out till alpha/beta at the earliest.
As far as the idea of soul scars, that is a good idea I think. I would say make the scars only about 10-20% as effective as a talent, but if a future life has the same or a related talent having the soul scar might make it easier to train in the use of the talent ONCE it is discover and unlocked.