Suana herself states its not all about Healing ability, but the desire to fix that which is broken. Like almost all AS the Yellow are more like scholars than Doctors. They seem to be more interested in study and Politics just like other AS. Which is why Romanda is amazed with how many Wise Women have such Talent with Healing.

These are the women with the calling, who all coincidentally are born with the Healing Talent? Think about it, the OP is something written into your genetic code on some level. You are born with it and each individual is fairly unique in how it expresses itself. Nowhere have we seen the ability to change ones inherent OP skills through training or other methods. Why should human interests effect your OP ability? Seems much more plausible that a natural proclivity would gently push a person down the path. Androl having a desire to Travel based on an inherent OP Talent seems much more plausible to me than his OP Talent deriving from him traveling all over. If that was the case Egwene would be a better Healer, she did train for it under Nynaeve.

In the end I doubt there is a "right" answer, but it's clear that one some level your personality and your OP Talents are tied together.